19. The formula

is used to solve the triangle problem in the preceding frame.

Carefully study the step-by-step solution which follows.

First, get the formula on paper ...

Now substitute the known values,

altitude = 9, base = 12, or ...

Next, square and add the known

values as indicated ...

Then extract the square root to

find the value of "c" ...

20. Solve for the unknown side of the triangle below.

Place your answer in the space provided.

Refer to frame 17 for the correct formula, then

refer to frame 19 for step-by-step procedures.

__________________Your answer