Exercise 4 Page 448

We are given the lengths of two of the triangle's sides, 5 yards and 9 yards. Let's add these values and find their sum. 5+9=14yardsNow we can recall the Triangle Inequality Theorem, which states the following. The sum of the lengths of any two sides of a triangle must be greater than the length of the third side. According to this theorem, the length of the third side must be less than the sum of the other two legs. In our case, it should be less than 14 yards. Let's compare the given options of the length of the third side with this value.

We can see that the first three options fully satisfy the above theorem. Therefore, the least possible measure of the third side is 14 yards. The answer is D.