The inside perimeter of a running track (shown in figure) is 400m. The length of each of the straight portion is 90m and the ends are semi-circles. If the track is everywhere 14m wide, find the area of the track. Also find the length of the outer running track.

Explanation

The inside perimeter of the track =400 m

Width of the track =14 m

The total length of the two straight portions =90+90=180 m

Therefore, the length of the remaining portion (Semi-circular portions) =400−180=220 m

Circumference of the two remaining semi-circular portions = ` pi r+pi r=2 pi r`

′r′ is the radius.

⇒`2 pi r=220`

⇒`2×227×r=220`

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