Please find the area

45

Step-by-step explanation:

There's a couple ways to do this, my method will find the area of the larger triangle and subtract the smaller triangle using only Pythagorean theorem.

Finding the side length adjacent to the 6 will allow us to solve the problem

6^2 + b^2 = 10^2

36 + b^2 = 100

b^2 = 64

b = 8

The larger triangle

Base: 8 + 15 = 23

Height: 6

23 * 6 * 0.5 = 69

The smaller triangle

Base: 8

Height: 6

6 * 8 * 0.5 = 24

Final Steps:

69 - 24 = 45

c

Step-by-step explanation:

800-899 = 3 schools

900-999 = 5 schools

1000-1099 = 8 schools

1100-1199 = 6 schools

1200-1299 = 3 schools