Practice!

Sample Problem

The perimeter of triangle ABC is 40 cm. If  divide BC, AC and AB into 4 equal parts, then what is the perimeter of the shaded region?

  cm

Solution

We see that each shaded triangle have a perimeter of

 .

We know that

  

So

 = 40 ÷ 4 = 10.

We are looking for the perimeter of

 6,

which is simply 10 × 6 = 60 cm.