Geometry. 12 15 9 6 10 n What is the length of side ‘n’ in the triangle at the right? Form ratios of corresponding sides: Use any two ratios to form a.

Geometry

1215

96

10nWhat is the length of side ‘n’

in the triangle at the right?

Form ratios of corresponding sides:

Use any two ratios to form a proportion:15

10

12

n

12

n

15

10

9

6

Cross multiply to solve the proportion: 15n = 120

n = 8 units

bhA2

1 Area of a triangle

Area of a square / rectanglewlA

Area of a parallelogramhbA

Area of a trapezoidhbbA )(2

121

12 in.

25 in.

Volume of rectangular prism = l × w × h

Center

Diameter

Radius

Chord

Central Angle

Circumference

Diameter = 2r

Radius = ½ d

To find the area of a circle…

A = r²

5 cm

Find the area of the given circle. Use 3.14 for π

A = (3.14) (5)²

A = r²

A = (3.14) (25)

A ≈ 78.5 sq cm

10 cm

Find the area of the given circle. Leave your answer in terms of

A = (π) (5)²

A = r²

A = (π) (25)

A = 25π sq cm

Given diameter = 10 cmRadius = ½ dRadius = 5 cm

To find the circumference of a circle…

C = d

12 cm

Find the circumference of the given circle. Use 3.14 for π

C = (3.14) (24)

C = d

C = (3.14) (24)

C ≈ 75.36 cm

10 cm

Find the circumference of the given circle. Leave the answer in terms of

C = (π) (10)

C = d

C = (π) (10)

C = 10π cm

To find the area of the sector of a circle…

A = r² (central angle / 360)

4 cm

Find the area of the given sector. Use 3.14 for π

A = (3.14) (4)² (60 / 360)

A = r² (central angle / 360)

A = (3.14) (16) (1 / 6)

A ≈ 8.37 sq cm

60˚

20 cm

Find the area of the given sector. Leave your answer in terms of π

A = (π) (10)² (90 / 360)

A = r² (central angle / 360)

A = (π) (100) (1 / 4)

A = 25π sq cm

90˚

Diameter = C ÷ πCircumference = π d

Coordinate Plane

x-axis

y-axis

origin

Ordered Pair

(-5, 4)

x-coordinate

y-coordinate

To find the area of the

given polygon, count the number of

unit squares inside the polygon.

To find the area of the given

polygon, count the number of unit squares in the length and width. Then

use the formula to calculate the

area.

OR

66 sq units