Chapter 39, Problem 25A

For Exercises 23 through 34, round the answers to 1 decimal place.

25. All dimensions in Figure 39-15 are in inches.Refer to the triangle shown.
a. Find S when $S=\frac{1}{2}\left(a+b+c\right).$

b. Find the area (A) when $A=\sqrt{S\left(S-a\right)\left(S-b\right)\left(S-c\right).}$