An acute triangle has sides measuring 10 cm and 16 cm. The length of the third side is unknown. Which best describes the range of possible values for the third side of the triangle? A x 18.9 B 12.5 26 D 6 < x < 26

Solution:

12.5 < x < 18.9

Reason:

To solve this problem, we can apply Pythagorean's theorem.

To find the upper bound:

We can set the two given legs as the 2 legs of a right triangle. This allows us to keep the angle under 90 degrees. So if we set the legs to be 10 and 16, then the third side must be:

10^2 + 16^2 = x^2

x^2 = 356

x is roughly equal to 18.9

For the lower bound, this time, we set x as one of the legs, and 10 as the other let. Since we know that the longest side is 16, we can set up an equation again:

x^2 + 10^2 = 16^2

x^2 = 16^2 - 10^2

x^2 = 156

x is roughly equal to 12.5

So we have found the bounds to be 12.5 < x < 18.9