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Tutors Answer Your Questions about Circles (FREE)
Question 206830: I tried to solve this problem but I didnt come to far, could someone help me with it?
Problem; Given that the equation of a circle is x^2+y^2-10x+4y+13=0,find íts center and its radius.
The way I tried to solve it;
(x-h)^2+(y-k)^2=r^2
(x^2-10x+9)+(y^2+4y+1)= -13+9+1
(I think I did something totally wrong here)
Click here to see answer by scott8148(3385)   |
Question 207633: Hello, I am a junior struggling with her summer homework.
Here is the question:
An arc of a circle has a measure of 80 degrees and a length of 88pi centemeters. What is the diameter of the circle?
Please help!
Thanks a lot!
Click here to see answer by Alan3354(6097)  |
Question 209376: I would be very appreciated if someone were to help me answer this problem. A circular planetarium has a center stage with a 9 foot radius and five outer rings of circles of seats. Each ring of seats is seven feet wide. What is the circumference of the largest circle?
C=2*pi*r
Click here to see answer by stanbon(26297)  |
Question 209636: Drawing: Rectangle containing 8 circles of equal size (4 on top row, 4 on bottom row)
Problem: Find the area of the rectangle if the radius of each circle is 3
What I know: The area of a circle is A=IIr^2 / A=3.14 x 3^2 / A=3.14 x 9 / A=28.26 so the area of the 8 circles would be 28.26 x 8=226.08, but is that really the area of the rectangle that contains the circles? Is there a formula for finding this answer?
Thank you for your help!
Click here to see answer by Earlsdon(4900) |
Question 211114: This isn't really a math homework question, but I need it for measuring a dress.
I need to cut out a circle with a 35 inch circumfrence for the bust of the dress. I don't know the radius or diameter, just that one measurment. Is there any way you can help?
Click here to see answer by Alan3354(6097) |
Question 211733: A square barn measures 14 meters on each side. A goat is tethered outside by a rope that is attached to one corner of the barn. The rope is 8 meters long.
Suppose the rope is made twice as long. On how many sqaure meters of land is the goat now able to graze?
Lastly, an addition to the barn was built making it rectangular with dimensions 14 by 20 meters. On how many square meters of land is the goat now able to graze?
Click here to see answer by Theo(675)  |
Question 206837: Could someone tell me if this is right?
Problem; What is the equation of the ellipse with foci at (0,-4) and (0,4) and the sum of its focal radii being 10?
My answer; 2a=10 a=5 (sum of focal radii)
(0+0/2, (4+4/2)= (0,4)
c=4 b^2=a^2-c^2=25-16=9
equation of the ellipse is;
(x-0)^2/25+(y-4)^2/9=1
Click here to see answer by zakiyahjones24(1) |
Question 215925: I have a square that is inscribed into a circle. The area of the square is 64 square centimeters. I need to find the area of the shaded portion of the circle. The square touches the circle at each corner. Between each corner, there is the shaded area (from corner to corner to the outside edge of the circle.
I hope this makes sense.
Click here to see answer by Theo(675) |
Question 216562: three concentric circles have the centers at O
OABC is a rectangle C lies on the middle circle
A lies on the center circle and B lies on the outer circle the radius of the center circle is three Find;area of center circle pi times 9
area of middle circle impossible
area of outer circle dont know
Click here to see answer by Alan3354(6097) |
Question 220101: I've tried this a couple different ways, but the answer wasn't right.
I know that the standard equation for a circle with the center at the origin is
X^2 + Y^2= r^2
but I can't figure out how to find the radius.
Center at origin and containing the point (-2,3)
I've tried using the midpoint formula, distance formula and also inputing the given point into the standard equation for which I got 15. But I'm supposed to end up with 13 for the radius. What am I doing wrong?
Click here to see answer by susanaramya(9) |
Question 220101: I've tried this a couple different ways, but the answer wasn't right.
I know that the standard equation for a circle with the center at the origin is
X^2 + Y^2= r^2
but I can't figure out how to find the radius.
Center at origin and containing the point (-2,3)
I've tried using the midpoint formula, distance formula and also inputing the given point into the standard equation for which I got 15. But I'm supposed to end up with 13 for the radius. What am I doing wrong?
Click here to see answer by nerdybill(2448)  |
Question 220101: I've tried this a couple different ways, but the answer wasn't right.
I know that the standard equation for a circle with the center at the origin is
X^2 + Y^2= r^2
but I can't figure out how to find the radius.
Center at origin and containing the point (-2,3)
I've tried using the midpoint formula, distance formula and also inputing the given point into the standard equation for which I got 15. But I'm supposed to end up with 13 for the radius. What am I doing wrong?
Click here to see answer by MathTherapy(337) |
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