I need help finding the lentlgth form a to c.

Hi there!
[tex]\large\boxed{AC \approx 483 ft}}[/tex]
AC is the hypotenuse, so we can use a trig formula to solve.
We are given the adjacent side, AB, so we must use cosine. Recall that:
cosθ = A/H
Thus:
cos(21.3) = 450 / H
Rearrange:
H = 450 / cos(21.3)
Use a calculator to evaluate:
H = 482.99 ≈ 483 ft.
Answer:
AC ≈ 483
Step-by-step explanation:
Using the cosine ratio in the right triangle
cos21.3° = [tex]\frac{adjacent}{hypotenuse}[/tex] = [tex]\frac{AB}{AC}[/tex] = [tex]\frac{450}{AC}[/tex] ( multiply both sides by AC )
AC × cos21.3° = 450 ( divide both sides by cos21.3° )
AC = [tex]\frac{450}{cos21.3}[/tex] ≈ 483 ( to the nearest whole number )