Grade 10 Math: formula sheet

Ratios, lines, shapes, trigonometry and money · 58 formulas · metric edition 1

Module 1 · Proportion & Percent
Math 10-1 Unit Price (Price per Unit Quantity)
p=Cmp = \frac{C}{m}
Price per unit of quantity, the number that makes two package sizes comparable on a shelf.
Math 10-2 Percent Change
c=xnew−xoldxoldc = \frac{x_{\text{new}} - x_{\text{old}}}{x_{\text{old}}}
Relative change from an old value to a new one, as a fraction of the old value.
Math 10-3 Recipe Scaling (Ingredient for a New Yield)
Q2=Q1⋅S2S1Q_2 = Q_1 \cdot \frac{S_2}{S_1}
Ingredient quantity rescaled from the yield a recipe was written for to the yield you actually want.
Math 10-4 Map Scale to Real Distance
d=m Sd = m\,S
Real distance from a map measurement times the scale denominator.
Math 10-5 Discount Price (Percentage Off)
S=L (1−d)S = L\,(1 - d)
Price after a percentage is taken off the list price, and the discount implied by any pair of list…
Math 10-6 Sales Tax and Total Price
T=P (1+r)T = P\,(1 + r)
Total payable from a pre-tax price and a tax rate, and the reverse: recovering the pre-tax price…
Module 2 · Linear Relations & Rates
Math 10-7 Slope Between Two Points
m=y2−y1x2−x1m = \frac{y_2 - y_1}{x_2 - x_1}
Steepness of a line as rise over run between two points.
Math 10-8 Slope-Intercept Form of a Line
y=mx+by = mx + b
Equation of a straight line from its slope and y-intercept.
Math 10-9 Slope from Standard Form of a Line
m=−ABm = -\frac{A}{B}
Slope of a line written in standard form Ax + By = C, read straight off the two coefficients…
Math 10-10 x-Intercept of a Line
xint=−bmx_{\text{int}} = -\frac{b}{m}
Where a line in slope-intercept form crosses the x-axis, found by setting y to zero and solving the…
Math 10-11 Point-Slope Form of a Line
y=y1+m(x−x1)y = y_1 + m(x - x_1)
Equation of a straight line through one known point with a known slope, giving the y-value at any x…
Math 10-12 Speed, Distance & Time
v=dtv = \tfrac{d}{t}
Average speed from distance travelled and elapsed time.
Math 10-13 Fuel Consumption (L/100 km)
C=100 VdC = \frac{100\,V}{d}
Fuel consumption in litres per hundred kilometres from the fuel burned and the distance covered.
Math 10-14 Miles per Gallon ↔ L/100 km
C=235.215MC = \dfrac{235.215}{M}
The reciprocal relation between litres per hundred kilometres and US miles per gallon: their…
Math 10-15 Midpoint Formula
xm=x1+x22x_m = \frac{x_1 + x_2}{2}
The coordinate halfway between two endpoints along one axis; apply it to x and again to y for the…
Math 10-16 Distance Formula (2D)
d=(x2−x1)2+(y2−y1)2d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}
Straight-line distance between two points in the coordinate plane.
Math 10-17 Pythagorean Theorem
a2+b2=c2a^{2} + b^{2} = c^{2}
Relates the three sides of a right triangle.
Module 3 · Area & Perimeter
Math 10-18 Rectangle Area
A=l⋅wA = l \cdot w
Area of a rectangle as length times width.
Math 10-19 Area of a Triangle
A=12bhA = \tfrac{1}{2} b h
Area from base and perpendicular height.
Math 10-20 Area of a Circle
A=πr2A = \pi r^{2}
Area enclosed by a circle of radius r.
Math 10-21 Trapezoid Area
A=a+b2⋅hA = \frac{a + b}{2} \cdot h
Area of a trapezoid as the average of its two parallel sides times the perpendicular height.
Math 10-22 Parallelogram Area
A=b⋅hA = b \cdot h
Area of a parallelogram from its base and perpendicular height.
Math 10-23 Rectangle Perimeter
P=2(l+w)P = 2(l + w)
Perimeter of a rectangle from its length and width.
Math 10-24 Square Perimeter
P=4sP = 4s
Perimeter of a square as four times its side length.
Math 10-25 Parallelogram Perimeter
P=2(a+b)P = 2(a + b)
Perimeter of a parallelogram from its two side lengths.
Math 10-26 Triangle Perimeter
P=a+b+cP = a + b + c
Perimeter of a triangle as the sum of its three sides.
Math 10-27 Circumference of a Circle
C=2πrC = 2 \pi r
Distance around a circle of radius r.
Math 10-28 Ellipse Perimeter (Ramanujan Approximation)
P≈π[3(a+b)−(3a+b)(a+3b)]P \approx \pi \left[ 3(a+b) - \sqrt{(3a+b)(a+3b)} \right]
Perimeter of an ellipse by Ramanujan's second approximation: accurate to better than one part in a…
Math 10-29 Circular Sector Area
A=12r2θA = \frac{1}{2} r^{2} \theta
Area of a pie-slice sector of a circle from its radius and central angle in radians.
Math 10-30 Arc Length
s=rθs = r \theta
Length of a circular arc as radius times central angle in radians.
Module 4 · Volume & Surface Area
Math 10-31 Rectangular Prism Volume
V=l⋅w⋅hV = l \cdot w \cdot h
Volume of a box as the product of its length, width, and height.
Math 10-32 Cube Volume
V=a3V = a^{3}
Volume of a cube as its edge length raised to the third power.
Math 10-33 Triangular Prism Volume
V=12bhtLV = \tfrac{1}{2} b h_t L
Volume of a triangular prism: the triangular end area times the prism length, from the triangle's…
Math 10-34 Prism Volume (General Cross-Section)
V=BLV = B L
Volume of any prism or extrusion whose cross-section does not change along its length:…
Math 10-35 Cylinder Volume
V=πr2hV = \pi r^{2} h
Volume of a right circular cylinder from its radius and height, using π ≈ 3.14159265.
Math 10-36 Cone Volume
V=13πr2hV = \frac{1}{3} \pi r^{2} h
Volume of a right circular cone (one-third of the matching cylinder) using π ≈ 3.14159265.
Math 10-37 Pyramid Volume
V=13BhV = \frac{1}{3} B h
Volume of any pyramid as one-third of its base area times its perpendicular height.
Math 10-38 Sphere Volume
V=43πr3V = \frac{4}{3} \pi r^{3}
Volume enclosed by a sphere of radius r, using π ≈ 3.14159265.
Math 10-39 Sphere Surface Area
S=4πr2S = 4 \pi r^{2}
Surface area of a sphere of radius r, using π ≈ 3.14159265.
Math 10-40 Rectangular Prism Surface Area
A=2(lw+lh+wh)A = 2(lw + lh + wh)
Total surface area of a box: three pairs of matching rectangular faces, from length, width and…
Math 10-41 Cube Surface Area
S=6a2S = 6 a^{2}
Surface area of a cube as six times the area of one square face.
Math 10-42 Cylinder Surface Area
S=2πr2+2πrhS = 2 \pi r^{2} + 2 \pi r h
Total surface area of a closed cylinder (two end caps plus the wrapped side) using π ≈ 3.14159265.
Math 10-43 Cylinder Lateral Surface Area
A=2πrhA = 2\pi r h
Area of a cylinder's curved wall only, with no end caps: the label on a can, the insulation around…
Math 10-44 Cone Lateral Surface Area
A=πrlA = \pi r l
Curved surface of a right circular cone from its base radius and slant height, excluding the base…
Math 10-45 Cone Slant Height
l=r2+h2l = \sqrt{r^2 + h^2}
Slant height of a right circular cone by Pythagoras on its axial cross-section, from base radius…
Math 10-46 Hemisphere Volume
V=23πr3V = \frac{2}{3}\pi r^3
Volume of half a sphere, exactly half of the full sphere's (4/3)*pi*r^3.
Math 10-47 Hemisphere Total Surface Area
A=3πr2A = 3\pi r^2
Total surface of a solid hemisphere: the curved half-sphere 2*pi*r^2 plus the flat circular base…
Module 5 · Right-triangle trigonometry
Math 10-48 Right-Triangle Sine Ratio (SOH)
sin⁡θ=oh\sin\theta = \frac{o}{h}
Relates an acute angle of a right triangle to its opposite side and the hypotenuse.
Math 10-49 Right-Triangle Cosine Ratio (CAH)
cos⁡θ=ah\cos\theta = \frac{a}{h}
Relates an acute angle of a right triangle to its adjacent side and the hypotenuse.
Math 10-50 Right-Triangle Tangent Ratio (TOA)
tan⁡θ=oa\tan\theta = \frac{o}{a}
Relates an acute angle of a right triangle to the ratio of its opposite and adjacent legs.
Math 10-51 Percent Grade from Rise and Run
G=100 ΔhLG = \frac{100\,\Delta h}{L}
Percent grade is one hundred times the vertical rise divided by the horizontal run, measured level,…
Math 10-52 Grade to Slope Angle
θ=arctan⁡ ⁣(G100)\theta = \arctan\!\left(\frac{G}{100}\right)
Converts a percent grade into the slope angle measured from horizontal, and back again with the…
Math 10-53 Slope Ratio (H:V) to Percent Grade
G=100nG = \frac{100}{n}
Converts an embankment slope quoted as n horizontal to one vertical into the equivalent percent…
Module 6 · Money & Interest
Math 10-54 Simple Interest
I=P r tI = P \, r \, t
Interest earned on a principal at a flat rate per period, without compounding.
Math 10-55 Compound Interest (Periodic)
A=P(1+rn)ntA = P \left( 1 + \frac{r}{n} \right)^{n t}
Amount after t periods when interest compounds n times per period at rate r.
Math 10-56 Effective Annual Rate from a Nominal Rate
EAR=(1+rm)m−1\mathit{EAR} = \left(1 + \frac{r}{m}\right)^{m} - 1
What a quoted nominal annual rate really costs or earns once it compounds m times a year: 12%…
Math 10-57 Rule of 72 (Doubling Time)
n≈0.72in \approx \frac{0.72}{i}
Mental-arithmetic estimate of how many periods it takes money to double at rate i: with the rate…
Math 10-58 Present Value
PV=FV(1+r)t\mathit{PV} = \frac{\mathit{FV}}{(1 + r)^{t}}
Today's value of a future amount, discounted at rate r per period.