Question

An ant is moving around a few food pieces of different shapes scattered on the floor. For which food-piece would the ant have to take a longer round? Remember, circumference of a circle can be obtained by using the expression $c=2\pi r$, where r is the radius of the circle.

Answer 1

(a) Perimeter of figure $=\frac{2\pi r}{2}+2r=r(\pi +2)=\frac{2.8}{2}(\pi +2)=7.19$ cm

(b) Perimeter $=1.5+1.5+2.8+\pi \left(\frac{2.8}{2}\right)=10.19$

(c) Perimeter $=\pi \left(\frac{2.8}{2}\right)+2+2=8.39$

Clearly, for food ${}^{\prime }{b}^{\prime }$ the ant has to go more.