Question

The areas of two concentric circles are 1386cm and 1886.5cm respectively. Find the width of the rings

Answer 1

To calculate radius of each triangle use their areas

Step-by-step explanation:

$A_{1}=$ π²$r_{1}$²

1386 =  (22÷7)$r_{1}$²

$r_{1}$² = 441

$r_{1}$ = 21 cm

$A_{2} =$ π$r_{2}$²

1886.5 = (22÷7)$r_{2}$²

$r_{2}$² = 600.25

$r_{2}$ = 24.5 cm

then width of ring is

$r_{1}-r_{2} = 24.5-21$

$width = 3.5$cm