Plane Geometry

Question 1

Sum of Interior Angles

Answer 1

S = (n-2)*180

Question 2

Interior Angles

Answer 2

Theta = [(n-2)*180]/n

Question 3

Sum of Exterior Angles

Answer 3

S = 360

Question 4

Exterior Angles

Answer 4

Beta = 360/n

Question 5

Area of Regular Polygons

Answer 5

A = (1/4)n(a^2)*cot(180/n)

Question 6

Area of Regular Polygon Inscribed in a Circle

Answer 6

A = (1/2)n(r^2)*sin(360/n)

Question 7

Area of Regular Polygon Circumscribing a Cirle

Answer 7

A = n(r^2)tan(180/n)

Question 8

Area of Triangle
(given all sides)

Answer 8

A =sqroot[s(s-a)(s-b)*(s-c)]
S= (a+b+c)/

Question 9

Area of Quadrilaterals
(given all sides and angles)

Answer 9

A = sqroot[(s-a)(s-b)
(s-c)(s-d)
- (abcd*(cos^2 theta)]
S=(a+b+c+d)/2
Theta = (A+C)/2 = (B+D)/2

Question 10

Area of Cyclic Quadrilateral

Answer 10

A = sqroot[(s-a)(s-b)(s-c)*(s-d)]
S = (a+b+c+d)/2

Question 11

Rectangle

Answer 11

A = L×W
P = 2(L×W)

Question 12

Trapezoid

Answer 12

A = (1/2)(a+b)h
P = a+b+L1+L2

Question 13

Circle

Answer 13

A = pir^2
C = 2pi*r

Question 14

Sector

Answer 14

A = (1/2)(r^2)(theta-rad)
S = r*(theta-rad)

Question 15

Ellipse

Answer 15

A = a*b

Question 16

Parabola

Answer 16

A = (2/3)bh