B. is the correct answer as 387 contains 80 and 8 * 10 = 80. I hope this helps!!
Answer:
AE = 7.5
Step-by-step explanation:
Since <BAC = , then;
<BAD = <DAE = <CAE = (complementary angles)
From ΔABC, applying the Pythagoras theorem to determine the length of side AC;
= +
= +
100 = + 25
= 100 - 25
= 75
AC =
Applying trigonometric function to ΔCAE,
Cos =
AE = × Cos
= 7.5
Therefore, AE = 7.5
An obtuse angle is an angle between 90*-180*
The total surface area of this prism would be 120 square feet.