Easy math problems!
#8 and #10

8. volume of cylinder is pi*r^2*h So V= pi * (radius)^2 * height =720* pi we know circumference = 2 * pi * r if we look at first equation. We can edit it like pi * r * r * h now we can say it kind of looks like circumference equation but missing 2 so we multiply both sides by 2 2 * pi * r * r * h = 2 * 720 * pi We can take out the 2 * pi * r and put in circumference (C) c * r * h = 1440 * pi We we know h is 20 so c * r * 20 = 1440 * pi c * r = 72 * pi we have to solve for r first so break circumference back up 2 * pi * r * r = 72 * pi r * r = 36 r = 6 plug into circum equation C = 2 * pi * 6 C = 12 * pi

10.the cylinders fill uo the box and if radius is 1.5 then diameter is 3. There are 5 in a row some 3 * 5 = 15 box length.

2 in a column so 2 * 3 = 6 box width

the height is 5

So

l * h * w = V

6 * 5 * 15 =V

V = 450

2.   2 3/5.

3.   2 1/2.

step-by-step explanation:

6 - 3 2/5

= 6 -   17/5

= 30/5 - 17/5

= 13/5

= 2 3/5 (answer).

5 1/4 - 2 3/4

= 21/4 - 11/4

= 10/4

= 2 1/2 (answer).