Triangle A has an area of 3 and two sides of lengths 3 and 6. Triangle B is similar to triangle A and has a side with a length of 11. What are the maximum and minimum possible areas of triangle B?

1 Answer
Feb 17, 2016

The triangle inequality states that the sum of any two sides of a triangle MUST be greater than the 3rd side. That implies the missing side of triangle A must be greater than 3!

Explanation:

Using the triangle inequality ...

x+3>6
x>3

So, the missing side of triangle A must fall between 3 and 6.

This means 3 is the shortest side and 6 is the longest side of triangle A.

Since area is proportional to the square of the ratio of the similar sides ...

minimum area =(116)2×3=1211210.1

maximum area =(113)2×3=121340.3

Hope that helped

P.S. - If you really want to know the length of the missing 3rd side of triangle A, you can use Heron's area formula and determine that the length is 3.325. I'll leave that proof to you :)