If a pentagon is regular, then all of the sides are the same length. This means that

So, if
, the lengths of the sides evaluate to

So, all the sides of the pentagon are 21 units long, and AB is 21 units long as well, because all sides are the same length.
The question states that both parts of Noshi's desk were shaped like trapezoids and both had a height of 3.
We know that the formula for area of a trapezoid is (a+b)/2 * h, where a and b are bases of the trapezoid and h is the height. Note: This is like any other form of trying to find the area, because we are doing base times height, however, we need to divide the sum of the bases by 2 to find the average base length.
Let's call the first trapezoid on the left Trapezoid A and the second slanted trapezoid Trapezoid B.
Area of Trapezoid A = (a+b)/2 * h = (5+8)/2 * 3 = 13/2 * 3 = 6.5 * 3 = 19.5 feet
Area of Trapezoid B = (a+b)/2 * h = (4+9)/2 * 3 = 13/2 * 3 = 6.5 * 3 = 19.5 feet
To find the area of Noshi's total desk, we simply need to add the areas of Trapezoid A and Trapezoid B together.
19.5 feet + 19.5 feet = 39 feet
Therefore, the area of Noshi's desk is 39 feet.
Hope this helps! :)
Answer:
hi I was wondering if I could come in
It's 21.125 hope this works good luck ;)
20? I’m not for sure maybe look in the book? That’s the answer I got and it was right