Solution
f(r) = 3.14
Now we have to find the area of the circle when the radius (r) = 4.
Plug in r = 4 in f(r) to get the area of the circle.
f(4) = 3.14
f(4) = 3.14 * 4 * 4
f(4) = 3.14 *16
f(4) = 50.24
The answer is C. 50.24
Answer:
225
Step-by-step explanation:
Mary = 3x (3 times Carey)
Carey = x
Barry = x/2 (Because Carey read twice as many as Barry, it means he read half the amount Carey did)
3x + x + x/2 = 405
4x + x/2 = 405
8x/2 + x/2 (treat these as fractions) = 405
9x/2 = 405
9x = 810 (cross multiply)
x = 90
Mary = 3(90) 270
Carey = 90
Barry = 90/2 45
Mary - Barry
270 - 45 = 225
Hope this helps! :)
Answer:
The standard error of the mean is 0.85.
Step-by-step explanation:
The given standard deviation of a population (σ) = 7.8
sample size (N) = 85
We have to find standard error of the mean.
The formula to find standard error of the mean
= (standard deviation of the distribution) / (square root of sample size)
= (σ) / (√N)
= 7.8 / (√85)
= 7.8 / 9.219544457
= 0.8460
= 0.85 (approximately taken to two decimal places)
We have got the required answer.
The standard error of the mean is 0.85.
The volume of a cylinder is the area of the base, times the height.
<span>The area of the circular base is, of course, π times the square of its radius. </span>
<span>So the volume of a cylinder, V, is </span>
<span>V = π h r^2 </span>
<span>where h is the height and r is the radius. </span>
<span>If we multiply the height by 3, the new height is 3h. </span>
<span>If we multiply the width by 3, that multiplies the radius (which is half the width) by 3 also. </span>
<span>So the new volume would be </span>
<span>π (3h) (3r)^2 = π (3h) (9r^2) = 27π h r^2 </span>
<span>which is 27 times π h r^2, the volume of the smaller pool. But we know that volume is 37 cubic feet. </span>
<span>So the volume of the larger pool is </span>
<span>27 * 37 cubic feet = 999 cubic feet [answer B] </span>
<span>This is an instance of a general rule: </span>
<span>If we multiply ALL the linear dimensions of an object by a factor F, </span>
<span>while keeping the shape the same (often termed "similar" in geometry), </span>
<span>that multiplies the volume by F^3 (the cube of F). </span>
<span>It also multiplies the surface area by F^2. </span>
<span>These rules are very useful, especially when you hit these questions on an exam under time constraints. If you know them, you'll save time you can use to work other questions.</span>
