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

step-by-step explanation:

always plug in x. in this case, x equals 4.

i'm going to first solve 4(2+3x)

1) 4(2+3(4)) use pemdas to solve.

i'm going to multiply whats in the parenthesis first, so 3 times 4=12.

2)4 (2+12) i'm then going to multiply 4 by both numbers in the parenthesis (because multiplying comes before adding)

4 times 2= 8.   4 times 12= 48

4) (8+48)= 56 (answer)

i'm then going to solve 8+12x and plug in 4 for x.

1) 8 +12(4)

multiplying comes before adding, so i'm gonna multiply 12 and 4.

12 times 4= 48.

2) 8+48=56

both equal the same!