Answer: radius r = 2 inches
height h = 6 inches
Step-by-step explanation:
Given;
Volume V = 24πin3
Volume of a cylinder is given by
V = πr^2h
h = V/πr^2. ....1
Where, h = height and r = radius of cylinder
For the surface area of the cylinder with open top. we have,
S = 2πrh + πr^2
For the cost of materials used, let k represent the cost of materials used for the body of the cylinder.
Then, for the bottom will be 3k
Total cost will be represented by C, which gives
C = 2πrhk + 3πr^2k. .....2
Substituting eqn 1 to 2, we have;
C = 2πrVk/πr^2 + 3πr^2k
C = 2Vk/r + 3πr^2k
The material cost is minimum at dC/dr = 0
dC/dr = -2Vk/r^2 + 6πrk =0
6πrk = 2Vk/r^2
r^3 = 2V/6π
r = (2×24π/6π)^-3
r = (8)^-3
r = 2
Substituting r = 2 into eqn1
h = 24π/π(2^2)
h = 24/4 = 6
h = 6
for any fraction a/b, the decimal format of it is just a ÷ b.
A)
is the number rational?
well, a rational number is one we can write as a ration or fraction, well clearly is a fraction so it is rational.
B)
can it be written as a repeating/recurring decimal? well, 9/20 is 0.45, so -9/20 is -0.45, no repeating decimal like 0.454545......... , just a plain vanilla -0.45, so nope.
C)
is it less than -0.4?
well, let's recall that for the negative side on the number line, the closer to 0, the larger the number, so then -1,000,000 is much smaller than -1, because -1 is closer to 0.
who is closer -0.4 or -0.45?
|--------------------- -0.45 -------- -0.40 ------------------- 0 --------------- 1 -------------------|
so, -0.45 is farther from 0, and therefore is smaller than -0.4, so yes.
Answer:
D. plane
Step-by-step explanation:
A. is incorrect because three points don't make a point.
B. is incorrect because all points in a ray are colinear.
C. is incorrect because the three points are not colinear.
D. is correct because, for a given three different points, there is a plane that contains them.
Steps in multiplying fractions. Remember: finding common denominator is not necessary in multiplying fractions.
Common denominators are only needed in adding and subtracting fractions.
14/15 * 5/2
Step 1. Multiply the numerators.
14 * 5 = 70
Step 2. Multiply the denominators
15 * 2 = 30
Step 3. Simplify the fraction.
70/30 = 2 10/30 = 2 1/3
*the fraction 10/30 can still be simplified by dividing both numbers by 10. Hence, 1/3.
Steps in Dividing fractions.
24/60 ÷ 8/15
Step 1. Get the reciprocal of the 2nd fraction. Reciprocal means the reverse of the fraction. Simply swap the places of the numbers.
Reciprocal of 8/15 is 15/8.
Step 2. Multiply the 1st fraction to the reciprocal of the 2nd fraction. Follow steps in multiplying fractions.
24/60 * 15/8 = (24*15) / (60*8) = 360/480
Step 3. Simplify the fraction.
360/480 = 9 / 12 = 3/4
360 ÷ 40 = 9 ; 9 ÷ 3 = 3
480 ÷ 40 = 12 ; 12 ÷ 3 = 4
