Question

An umbrella has 8 ribs which are equally spaced.

Answer 1

Since the ribs are equally spaced , so the angle made by two consecutive ribs at the centre = ( 360/8)° = 45° .


Area between two consecutive ribs = Area of a sector of a circle with r = 42 cm and ¢ = 45° = ( 45/360 × 22/7 × 42 × 42 ) cm².



=> 693 cm².

Answer 2

$42 \div 8 = 5.25$
so
$5.25 \times 4 = 21$
circumstance is 21 cm