I'm having trouble in Geometry and can not figure these out, I've always been horrible at math PLEASE HELP!

Question

1 Find the volume of a rectangle solid with length 7 in. width 5 in.,
and height of 3 in.

2. Find the lateral area of a regular triangular pyramid with base edge
4 ft. and slant height 6 ft.

3. Find the volume of a regular square pyramid with base edge 2 ft. and
height 9 ft.

4. Find the volume of a right cone with radius 3m and height 8 m

5. Find the volume of a sphere with a radius 6 ft.

Answer 1

Hi,

1 Find the volume of a rectangle solid with length 7 in. width 5 in., and height of 3 in.

Formula is Volume = length x width x height
V = LWH = 7 x 5 x 3 = 105 cubic inches

2. Find the lateral area of a regular triangular pyramid with base edge
4 ft. and slant height 6 ft.

The perimeter of the square base is 4 + 4 + 4 + 4 = 16

Lateral Area Formula for Pyramids:
LA = 1/2 x perimeter of base x slant height
LA = 1/2 x 16 x 6 = 48 square feet.


3. Find the volume of a regular square pyramid with base edge 2 ft. and height 9 ft.

Since the base is a square, the length and width are both 2.
Formula is Volume = 1/3 x length x width x height
V = 1/3 x LWH = 1/3 x 2 x 2 x 9 = 12 cubic feet


4. Find the volume of a right cone with radius 3m and height 8 m

Volume of a cone V = 1/3 Pi r^2h where Pi = 3.14, so
V = 1/3 x 3.14 x 3^2 x 8
V = 1/3 x 3.14 x 9 x 8 Since 1/3 x 9 = 3, combine them first
V = 3 x 3.14 x 8 Then 3 x 8 = 24, so
V = 3.14 x 24 This multiplies to
V = 75.36 cubic meters

5. Find the volume of a sphere with a radius 6 ft.

Volume of a sphere : V = 4/3 x Pi x r^3
V = 4/3 x 3.14 x 6^3
V = 4/3 x 3.14 x 216
V = 288 x 3.14
V = 904.32 cubic feet.

I hope that helps!! Your first 3 answers sure didn't. :-)

Answer 2

1. Volume of a rectangle = L x W x H. So, 7 x 5 x 3 = 105 in. cubed.

2. First of all, we must picture a pyramid in our heads, which, if it is a triangular pyramid, has a triangle base and 3 sides that are also triangles.
The area of a triangle is 1/2(b x h), and they give us the "height" (slant height) of the triangle, 6ft, and the length of the base, 4 ft. This means that for one side of this pyramid, we have 1/2 (4 x 6), which is 12 ft. squared. Now we multiply it times 4, because there are a total of 4 sides, which gives us a total lateral area of 48 square feet.

3. Volume of a pyramid = 1/3 (Area of base)(height)

4. Volume of a cone = 1/3 (Area of base)(height)

5. Volume of a sphere = 4 divided by 3 x pi x radius cubed

Answer 3

1. Length x Height x Depth = Volume
In this case, 7 x 5 x 3 = 105.
2. Draw a picture and find what is "lateral area".
3. Uh
4. 1/3 x Base Area x Height = Volume of Cone
In this case, 1/3 x (9 x pi) x 8 = 24 cubic meters. The pi is a symbol, which is 3.141592 . . . Note: to find the base area, you have to find the area of a circle by mulitplying the quantity of the multiplication of two radii by pi. r x r x pi.
5. V = (4/3) x pi x 6 x 6 x 6. You may use a calculator to find the answer. The volume of a sphere is the quantity of 4/3 times the quantity of pi times the quantity of the multiplication of three radii.

Answer 4

1. 105 in

3. 20 ft..

I'm only in grade 8 ...thats all I can do at the top of my head

Answer 5

1. 105 in.^3
2. 48 ft.^2
3. 12 ft.^3
4. 75.36 m^3
5. 904.32 ft^3

Im only in seventh grade so some of them may not be correct... sorry if they are wrong... I tried =p

Answer 6

use your book. look in the index for the formulas and plug in to solve

Answer 7

Go to a psychologist and get an evaluation to see if you have dyscalculia and you won't have to do it. lol! worked for me

Answer 8

i used to be really good at this.. its obviously completely left my memory.. i wish i could help sorry dear! goodluck though! =]

Answer 9

h

Answer 10

i don't remember how to do these, sorry