Answer:

Step-by-step explanation:
First we'll work out the surface area of the pink figure.
That's the area of the two 5 by 6 rectangles on the top and bottom, plus the area of the two 5 by 20 and two 6 by 20 rectangles on the sides.
However, we note that the purple figure is blocking out a 6 by 12 section on the pink figure, so we'll need to subtract this.
The above works out to
.
Then we'll work out the surface area of the purple figure.
This will be the area of the two 4 by 6 rectangles at the top and bottom, plus the area of the two 4 by 12 and one 6 by 12 rectangles on the sides. Note that there's only one 6 by 12 rectangle because the other face is joined to the pink figure, so it's blocked out.
That's
.
So the total surface area is
.
The simplified expression of
is 
<h3>How to simplify the expression?</h3>
The expression is given as:

Divide 162 and 2 by 2

Take the square root of 81

Apply the quotient rule of indices

Evaluate the difference

Take the square root of x^18

Hence, the simplified expression of
is 
Read more about expressions at:
brainly.com/question/723406
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Let us draw a picture to make the things more clear.
Attached is the image.
We have been given that

Therefore, we have

Now, in triangle bcd, we have

Now, in triangle acb, we have

Thus, ad is 15 cm.
Answer:
<h2>62.8 ft</h2>
Step-by-step explanation: