Depends on where you are in the math book but this would be the most simple way.
n= number
sqar(-1) = i
Answer:

Step-by-step explanation:
Given

Required
Determine KBC
Since BK is a bisector of ABC at B,
this implies that:

Substitute 28.3 for ABK

Reorder

Answer:
2376 square feet
Step-by-step explanation:
40 x 15 = 600
40 x 24 = 960
1/2 x (24 x 9) = 108
600 + 600 + 960 + 108 + 108 = 2376