A running track in the shape of an oval is shown. The ends of the track form semicircles.
A running track is shown. The left and right edges of the track are identical semicircles. The top and bottom edges of the track are straight lines. The track has width 42 m and length of one straight edge 110 m.
What is the perimeter of the inside of the track? (π = 3.14)
304.00 m
351.88 m
912.37 m
1,604.74 m
To find the inside perimeter of the track, we need to subtract the width of the track from the outside perimeter.
The outside perimeter of the track consists of two semicircles and two straight edges.
The circumference of each semicircle is π * r, where r is the radius. Since the ends of the track form semicircles, the radius is half of the length of the straight edge, which is 110 / 2 = 55 m.
So, the circumference of each semicircle is π * 55 = 3.14 * 55 = 172.7 m.
The length of each straight edge is 110 m.
Therefore, the outside perimeter of the track is 2 * 172.7 + 2 * 110 = 317.4 + 220 = 537.4 m.
Now, we need to subtract the width of the track to find the inside perimeter.
The width of the track is 42 m.
So, the inside perimeter of the track is 537.4 - 2 * 42 = 537.4 - 84 = 453.4 m.
The answer is 453.4 m.
304.00 m
351.88 m
912.37 m
1,604.74 m pick one
The correct answer is 351.88 m.
2 pi r +220 =( 2 * 3.14 * 21) + 220 = about 340
so 351.88 looks good