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.
Given:
Area of rectangular pool = 640 square feet
The length is 12 feet shorter than the width.
To find:
The length and width of the pool.
Solution:
Let width of the pool = x feet
Then, Length of the pool = (x-12) feet
Area of a rectangle is
Area of pool is 640 square feet. So,
Splitting the middle term, we get
Using zero product property, we get
Dimensions cannot be negative. So, x=32.
Now,
Width of the pool = 32 feet
Length of the pool = 32-12 = 20 feet
Therefore, the length of the pool is 20 feet and width is 32 feet.