In any trapezoid, the area is given by

where B and b are the two bases, and h is the height. You're given all these elements already, so you only need to plug the values in:

Answer:
31869.5
Step-by-step explanation:
Answer:
(a)80 feet
(b)$120,000
Step-by-step explanation:
<u>Part A</u>
<u>Intersecting Secant-Tangent Theorem</u>
If a tangent segment and a secant segment are drawn to a circle from an exterior point, then the square of the measure of the tangent segment is equal to the product of the measures of the secant segment and its external secant segment.
In the attached diagram, the theorem applied is:

Comparing with our diagram:
|AX|=30 feet
|UX|=10 feet
Length of the Bridge,L
Therefore:

900=10(L+10)
L+10=900/10
L+10=90
L=90-10=80 feet
Length of the Bridge=80 feet
<u>Part B</u>
If each foot costs $1500
Cost of the bridge=$1500*80=$120,000