3 math problems. Help please and thank you.?

Question

One cubic foot will hold 7.5 gallons of water. If Andrew's waterbed mattress measures 7 1/2 feet by 4 feet by 4 inches, how many gallons of water will he need to fill the mattress?


A bathroom shower wall is 4 feet wide and 8 feet high. Mrs. Rivera wants to put beige 4" x 6" tiles on the wall. What is the minimum number of tiles that she needs?



A swimming pool 40 feet long and 18 feet wide is filled to an average depth of 5 feet. Given that 1 gallon of water has a volume of 231 cubic inches, approximately how many gallons of water are in the pool?

Thank you for your kindness. These are from a packet about congruent figures and similar figures. I am genunely puzzled! Please help by explaining! If you can only do one I will still appreciate your time and effort.

Answer 1

Convert to inches

7 1/2 feet =

12 x 7 = 84

84 + 6 = 90 inches
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4 feet =

12 x 4 = 48 inches


90 x 48 x 4 =

4320 x 4 =

17280 inches

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1 cubic foot =

12 x 12 x 12 =

144 x 12 =

1728 Inches

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Divide 17280 by 17280

17280 / 1728 = 10

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Multiply 7.5 times 10

7.5 x 10 = 75 gallons

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convert feet to inches

12 x 4 = 48 inches

12 x 8 = 96 incheds

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Multiply 48 times 96

48 x 96 = 4608 square inches

4" x 6" = 24 square inches

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Divide 4608 by 24

4608 / 24 =

192

192 is the miminum number of tiles

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Answer 2

First problem: Volume= length X width X height. Since you know one unit volume (a cubic foot) of water is the same as 7.5 gallons of water, you can easily make a proportion if you can determine the volume of the waterbed in cubic feet.
All the measurements of the waterbed must be in feet. If they aren't, you must change them to the correct measurements in feet. One measurement is NOT in feet. The 4 inch measurement can be changed to (4/12) of a foot or (1/3) ft.
So the Volume of the bed is (15/2)ft X (4)ft X (1/3)ft
(60/6)cubic feet
10 cubic feet
Since 1 cubic foot is the same as 7.2 gallons; 10 cubic fett is 10 X 7.2 gallons or 72 gallons.

Answer 3

It seems to me that most of the other answers miss the inch to feet conversion! You don't need help like that...

First get all your units to be the same, then multiply or divide as necessary. 12 inches = 1 foot, that's all you need to know:

7.5x4x1/3 feet x feet x feet = 10 cubic feet. Each one of those holds 7.5 gallons of water/cubic foot. So, 75 Gallons of water will be needed.

Each tile is 1/3x1/2 feet square, that's 1/6 square foot.
The wall is 32 square feet. So 32 : (1/6) = 32x6 = 192 tiles.


I'll leave the last one up to you. cubic inch = 1/12 of a foot cubed! ie. 1 cubic foot = 12x12x12 cubic inches.

Answer 4

1: Volume = 7.5 x 4 x 4/12 = 10 cu. ft
Therefore, # of gallons required = 10 x 7.5 = 75 Gallons

2) Area of wall = 4 x 8 = 32 sq. ft
Area of tiles = 4/12 x 6/12 = 0.167 sq ft
# of tiles required = 32/0.167 = 192 tiles

3) Volume of water in pool = 40 x 18 x 5 = 3600 cu ft = 6220800 cu inches (= 3600 x 12 x 12 x 12)
# of gals of water = 6220800/231 = 26930 gals

Hope this helps.

Answer 5

1) 75 gallons
2) 192 tiles
3) 26,930 gallons

#1 volume = 7.5 ft. * 4ft. * 1/3ft. = 10 cubic feet
if 1 cubic foot is 7.5 gallons, then 10 cubic feet is 75 gallons

#2 the wall area = 8ft. x 4ft. = 32 sq. ft.
each tile area = 1/3 ft. x 1/2ft. = 1/6 sq. ft.
to find the number of tiles just divide 32 by 1/6 and you get 192 tiles

#3 you need to convert everything to inches. volume = 480in. (40ft.) x 216in. (18ft.) x 60in. (5ft) = 6,220,800 cubic inches.
- if one gallon is 231 cubic inches, then just divide 6,220,800 by 231 and you get 26929.87013 gallons. round to 26,930

Answer 6

1. 7.5 X 4 X 6.33 X 7.5 gallons

2. 4 X 8 divided by 0.33 X 0.5

3. 12(40 X18 X 5) divided by 231

Just do youir own arithmetic

Answer 7

75 gallons, 192 tiles, 26,929.87 gallons

Answer 8

try the first one...

you need volume of water bed, 7.5 feet times 4.33 feet gives you a number in your calculator right?

then multiply that number by 7.5 to get gallons

amazingly you will see 243.56... in your calculator screen

does that work for you?