bumblebee123
Junior Member
- Joined
- Jan 3, 2018
- Messages
- 200
question: the diagram shows the markings of a running track lane. the inside of the lane consists of two straight lines, each of length d metres and two semicircles, each with a radius of r metres. the perimeter of the inside of the lane is 400 metres.
a) explain why 2 π r + 2d = 400
I think I understand this. The circumference of the inner semicircles is going to make a circle, so 2 π r. The lines = d and there are two lines so their perimeter is 2d.
b) the lane is 1 metre wide. the outside lane consists of two straight lines, each of length d metres, and two semicircles. Calculate the perimeter of the outside of the lane
how would I figure this out? any help would be really appreciated