8.1 and 8.3 Review

Vocabulary

100

A circle is the set of all points in a plane that are the same distance away from a point called the...

center

200

The distance from the center to any point on the circle is called...

the radius

300

The distance across the circle through the center is called...

the diameter

400

The distance around a circle is... and its formula is...

the circumference

C = pi(d)

C = 2(pi)r

500

The formula for the area of a circle is...

A = pi(r²)

Radius or Diameter?

100

Given: Radius = 7 mm

The diameter is...

14 mm

200

Given: Diameter = 50 in

The radius is...

25 in

300

Given: Diameter = 150 ft

The radius is...

75 ft

400

Given: Radius = x

The diameter is...

2x

500

Given: Diameter = xy

The radius is 

(xy)/2

Circumference

100

Given: Radius = 5 mm

The circumference is...

31.4 mm

200

Given: Diameter = 10 m

The circumference is...

31.4 m

300

Given: Radius = 2.1 yd

The circumference is...

13.188 yd

400

Given: Diameter = 82 cm

The circumference is...

257.48 cm

500

Given: Diameter = xy

The circumference is...

pi(xy)

Area

100

Given: Radius = 5 mm

The area is...

75.5 mm²

200

Given: Radius = 8 cm

The area is...

200.96 cm²

300

Given: Diameter = 10 in

The area is...

78.5 in²

400

Given: Diameter = 5 mi

The area is...

19.625 mi²

500

Given: Radius = xy mm

The area is...

A = pi(xy)²

Semi Circle

100

Given: Radius = 5 mm

The area of the semicircle is...

39.25 mm²

200

Given: Diameter = 14 m

The area of the semicircle is...

76.93 m²

300

Given: Radius = 20 in

The area of the semicircle is...

628 in²

400

Given: Radius = 5 mm

The circumference of the semicircle is...

25.7 mm

500

Given: Diameter = 16 mi

The circumference of the semicircle is...

41.12 mi