In the diagram above MN is a chord of a circle KMN centre O and radius 10cm. If < MON = 140°, find, to the nearest cm, the length of the chord MN.
A.
10cm
B.
19cm
C.
17cm
D.
12cm
Correct answer is B
Find the diagram
Sin 70°
x = 10 Sin 70°
= 9.3969
Hence, length of chord MN = 2x
= 2 × 9.3969
= 18.79
= 19cm (nearest cm)