Question

7.
The inner edge of a circular running-track is
440 m long. If the track is 10 m wide, find the
length of the outer edge of the track.
​

Answer 1

Answer:

502.4 m

Step-by-step explanation:

Given,

Inner Circumference = 440 m

Width = 10 m

Let $r_{1}$ be inner radius & $r_{2}$ be outer radius .

∴ 440 = 2 x 22/7 x $r_{1}$

⇒ 220 = 22/7 x $r_{1}$

⇒ $r_{1}$ = 70 m

$r_{2}$ = 10 m + $r_{1}$

⇒$r_{2}$ = 80 m

Outer circumference = 2 x 22/7 x $r_{2}$

⇒ Outer circumference = 2 x 22/7 x 80

⇒ Outer circumference = 160 x 22/7

⇒ Outer circumference = 502.4 m