1. You have 3500 in savings for 9 months at a rate of 4.5%. How much will you have at the end of that time?

Question

Ans. my book says: 3,618.13
I come up with: 118,125

2. Scale reads 1 inch = 24 inches for a house window. If window measures 1 3/4 inches, what is the actual length?

Ans. my book says: 3 ft 6 in
I come with 3.5

3. Scale reads 1 inch = 8 ft. If the width of the drawing is 2.25 inches and the length is 4 inches, what is the actual length of the deck's diagonal?

Ans. my book says: 37 ft.
I don't know how they came up with 37 ft.

Answer 1

1.
amount = 3500 + 3500(.045)(9/12)
= 3500 + 118.125
= 3618.13

Your answer is only the interest earned, you must add this to what you already have.

2.
you have 3.5 feet
= 3 feet + 1/2 foot ----- .5 = 1/2
= 3feet , 6 inches

3.
so the actual width of the deck is 18 ft and the length is 32 feet
by Pythagoras
H^2 = 18^2 + 32^2 = 1348
H = √1348 = 36.7 or rounded to 37 feet

Answer 2

1.
Can't imagine how you got that answer. Even using 45%, I only get 99169!

However, 4.5% = .045 and that's an annual rate.
You want a monthly rate. Furthermore, you don't say whether that's simple interest or compounded monthly

Simple: 3500(1+.045/12*9) = 3618.13
so, I guess that's it.

2.
the scale indicates that the real dimensions are 24 times as large as the scale drawing.

1 3/4 = 7/4
7/4*24 = 42 inches = 3'6"

You are correct. Since a foot is 12 inches, the .5 foot is 6 inches.
3.5 feet = 3 feet 6 inches!
Keep track of the units, and don't lose track of conversions needed.

3.
This is just like #2.
1" = 8'
2.2" = 2.25(8') = 18'
4" = 4(8') = 32'

so, you have a rectangle that is 18x32.
Recall the Pythagorean Theorem, to see that the diagonal is
√(18^2+32^2) = √(324+1024) = √1348 = 36.7, or 37'