Answer:
see explanation
Step-by-step explanation:
Using the ratio equality for circles
[tex]\frac{arc}{C}[/tex] = [tex]\frac{angleatcentre}{360}[/tex]
(a)
Note the angle at the centre of the shaded arc is 360° - 90° = 270°, thus
[tex]\frac{45}{C}[/tex] = [tex]\frac{270}{360}[/tex] = [tex]\frac{3}{4}[/tex] ( cross- multiply )
3C = 180 ( divide both sides by 3 )
C = 60 mm
(b)
Note the angle at the centre of the shaded arc is 360° - 135° = 225°, thus
[tex]\frac{3.3}{C}[/tex] = [tex]\frac{225}{360}[/tex] ( cross- multiply )
225C = 1188 ( divide both sides by 225 )
C = 5.28 cm
