Question

Determine the best answer

6 points
MULTIPLE CHOICE Find the length of BC. (Lesson 10-2)
B
21 cm
C
168°
A 18°
C 168°
B 2.20 cm
D 30.79 cm
A

Answer 1

angle of bc= 180-168= 12°

length of bc= 12/360 × π × diameter

= 12/360 × 22/7 × 21

= 12/360 × 66

= 2,20 cm (b)

Answer 2

Let’s assume the point in the centre is the origin of the circle.

This means the radius is 21/2 = 10.5cm.

180 - 168 = 12 degrees as the angle between BC.

Circumference of a sector is:

Angle/360 • pi • diameter

=12/360 • pi • 21 cm

= 2.19 cm = 2.20 cm

Which is option B