Answer:
9ft
Step-by-step explanation:
Use the pythagorean theorem.
15^2 = 12^2 + x^2
solve for x
x^2 = 81
x = 9
Vertical angles are equal
4x = 45 + 15
4x = 60
x = 60/4
x = 15
10.5, 11, 11.5, 12, 12.5...this is an arithmetic sequence with a common difference of 0.5
an = a1 + (n - 1) * d
n = term to find = 23
a1 = first term = 10.5
d = common difference = 0.5
sub and solve
a(23) = 10.5 + (23 - 1) * 0.5
a(23) = 10.5 + 22 * 0.5
a(23) = 10.5 + 11
a(23) = 21.5 <===