Geometry

Question 1

Sum of interior angles of a polygon

Answer 1

S = (n-2)180°

Question 2

Each interior angle in a regular polygon

Answer 2

θ = ((n-2)180°)/n

Question 3

Distance between two points

Answer 3

D = √((x2-x1)²+(y2-y1)²)

Question 4

Area of triangle inscribed in a circle, At

Answer 4

At = abc/4r
-where a,b,c = sides of the triangle
r = radius of circle

Question 5

Area of triangle circumscribing a circle, At

Answer 5

At = rS
-where r = radius of circle
S = semiperimeter of triangle

Question 6

Formula for semiperimeter, S

Answer 6

S = (1/2)(perimeter)

Question 7

Hero’s formula

Answer 7

At = √(S(S-a)(S-b)(S-c))
-where At = area of triangle
S = semiperimeter of triangle
a,b,c = sides of triangle

Question 8

Latus rectum of ellipse

Answer 8

2b²/a
-b = length between center and midpoint of major axis
-a = half of major axis. Length from center to vertex

Question 9

Eccentricity, e, of ellipse

Answer 9

e = c/a = a/d = ( √(a²-b²) ) / a
-c = length from center to focus
-d = length from center to directrix

Question 10

Area of a trapezoid

Answer 10

( (a+b) / 2 ) * h

Question 11

Volume of a sphere

Answer 11

(4/3)πr³

Question 12

Surface area of a sphere

Answer 12

4πr²

Question 13

Volume of a pyramid

Answer 13

(1/3)Ah
-A = base area

Question 14

Volume of a cone

Answer 14

(1/3) πr²h