Answer:
Step-by-step explanation:
15 x 7 = 105
The gap is either 9 x 7 =63 or 12 x 7 = 84
105 - 84 = 21
105 - 63 = 42
So the shaded area is either is 21 or 42
The answer is 21 + 4x.
You find this answer by adding up all the sides.
9+12+4x= 21+4x ... you don't add 4x because it has a variable that we do not know of the value.
A = 1/2aP
P = number of sides x length of each side
P = 8 x 5.8
P = 46.4
A= 1/2 x 7 x 46.4
A = 162.4