# Geometry Formulas

### Description

Here are all the formulas we use in Geometry. There are some *quality core* formulas as well.
Flashcards by Selam H, updated more than 1 year ago
 Created by Selam H about 10 years ago
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## Resource summary

 Question Answer Standard Form $Ax+By=C$ Slope M=$\frac{y_2-y_1}{x_2-x_1}$ Slope-Intercept Form $y=mx+b$ Point-Slope Form $y-y_1=m(x-x_1)$ Distance on a Number Line D=$|a-b|$ Distance on a Coordinate Plane D=$\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$ Distance in Space (3D) D=$\sqrt{(x_2-x_1)^2+(y_2-y_1)^2+(z_2-z_1)^2}$ Distance Arc Length L=$\frac{N}{360}·2\pi·r$ Midpoint on a Number Line M=$\frac{a+b}{2}$ Midpoint on a Coordinate Plane M=$\frac{x_1+x_2}{2},$$\frac{y_1+y_2}{2}$ Midpoint in Space (3D) M=$\frac{x_1+x_2}{2},$$\frac{y_1+y_2}{2},$$\frac{z_1+z_2}{2}$ Perimeter of a Square P=$4s$ (s=side) Perimeter of a Rectangle P=$2l+2w$ (l=length, w=width) Circumference of a Circle C=$2\pi·r,\pi·d$ Area of a Square A=$s^2, lw$ Area of a Rectangle A=$lw, bh$ Area of a Parallelogram A=$bh$ Area of a Trapezoid A=$\frac{1}{2}h(b_1+b_2)$ Area of Rhombus A=$\frac{1}{2}d_1d_2, bh$ Area of Triangle A=$\frac{1}{2}bh$ Area of Regular Polygon A=$\frac{1}{2}Pa$ Area of a Circle A=$\pi·r^2$ Area of Sector of a Circle A=$\frac{N}{360}\·pi·r^2$ Quadratic Formula $\frac{-b±√b^2-4ac}{2a}$ Lateral Surface Area of Prism L=$Ph$ Lateral Surface Area of a Cylinder L=$2\pi·r·h$ Lateral Surface Area of a Pyramid L=$\frac{1}{2}Pl$ Lateral Surface Area of a Cone L=$\pi·r·l$ Total Surface Area of a Sphere SA=$4\pi·r^2$ Total Surface Area of a Hemisphere SA=$3\pi·r^2$ Volume of a Pyramid V=$\frac{1}{3}Bh$ Volume of a Rectangular Prism V=$Bh$ Volume of a Right Circular Cylinder V=$2\pi·r^2+2\pi·r·h$ Volume of a Right Circular Cone V=$\frac{1}{3}·pi·r^2·h$ Volume of a Sphere SA=$\frac{3}{4}·pi·r^3$ Surface Area of a Regular Prism or Cylinder (2-based) SA= $Ph+2B$ *If you are finding the surface area of a cylinder, replace P (perimiter) with Circumfrance. Surface Area of a Regular Pyramid or Cone (1-based) A=$\frac{1}{2}Pl+B$ *If you are finding the surface area of a cone, replace P (perimiter) with Circumfrance **l= slanted height Pythagorean Theorem $a^2+b^2=c^2$ $\sin A=$$\frac{a}{c}$ $\cos A=$$\frac{b}{c}$ $\tan A=$$\frac{a}{b}$ Sum of Degree Measures of the Interior Angles of a Polygon $180(n-2)$ (n=number of sides) Degree Measure of an Interior Angle of a Regular Polygon $\frac{180(n-2)}{n}$ ⊥ is perpendicular to || is parallel to ≅ is congruent to ∼ is similar to ≈ is approximately equal to ∆ABC triangle ABC ∠ABC angle ABC m∠ABC the degree measure of angle ABC Circle O circle with center point O

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