Number of Payphones
2 answers:
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Answer:
Option A is the correct answer.
Explanation:
The given pyramid has 3 lateral triangular side as shown below.
Base of triangle = 12 unit
We need to find perpendicular.
By Pythagoras theorem we have
Perpendicular² = 10²-6²
Perpendicular = 8 unit
So area of 1 lateral triangle = 1/2 x Base x Perpendicular.
= 1/2 x 12 x 8 = 48 unit²
Area of lateral side = 3 x 48 = 144 unit²
Option A is the correct answer.
