2.
The radii of two circles are 3 cm and 9 cm. Find the ratio of their circumferences.
3.
Find the length of the arc in a circle if the radius of the circle is 24 cm and the degree of the arc is 90°.
4.
A circle has radius 8 cm and XY is a chord in the circle of length 8√3 cm. Find the length of arc XY.
6.
A circle has a radius of 15. Find the diameter (D) and the area (A).
7.
A circle has a radius of 7. Find the diameter (D) and the area (A).
13.
Find the circumference of a circle if the area is (9/25)pie ft^2.
16.
Find the area of a circle whose radius is 2.5 m.
20.
Find the degree measure of a sector in a circle if the radius of the circle is 20 feet and the area of the sector is 40pie ft^2.
21.
A spotlight creates a circle of light on a smooth surface. The radius of the circle is 15 feet. Rounding to the nearest foot, find the length of a square with the same area as the circle.
submission 30
2006-10-02 06:03:18 · 7 answers · asked by qtgyjda89 2 in Science & Mathematics ➔ Mathematics
2.
The radii of two circles are 3 cm and 9 cm. Find the ratio of their circumferences. 1:3
3.
Find the length of the arc in a circle if the radius of the circle is 24 cm and the degree of the arc is 90°.l=x/360*2pir
=90/360 *2pi*24=12 pi cm
4.
A circle has radius 8 cm and XY is a chord in the circle of length 8√3 cm. Find the length of arc XY.
6.
A circle has a radius of 15. Find the diameter (D) and the area (A).diameter=30 and area=pi(15)^2=225 pi
7.
A circle has a radius of 7. Find the diameter (D) and the area (A)
diameter=14 and area=(22/7)7^2=154 sq. units.
13.
Find the circumference of a circle if the area is (9/25)pie ft^2.
pi r^2=9/25pi
r^2=9/25
r=3/5'
16.
Find the area of a circle whose radius is 2.5 m.area=pi(2.5)^2
=6.25pi m^2
20.
Find the degree measure of a sector in a circle if the radius of the circle is 20 feet and the area of the sector is 40pie ft^2.
area=(x/360)*pir^2
40pi=(x/360)*pi20^2
x=40*360/400=36*
21.
A spotlight creates a circle of light on a smooth surface. The radius of the circle is 15 feet. Rounding to the nearest foot, find the length of a square with the same area as the circle.
a^2=3.14*15^2
a=27'
2006-10-02 06:14:41 · answer #1 · answered by raj 7 · 0⤊ 0⤋
2. C=2*pi*r, so the ratio is the same as that of their radii, 1:3.
3. 1/4 of the way around the circle, so (pi/2)*24=12pi.
4. The arc has an angle of 120 degrees, so it's (2*pi/3)*8=16*pi/3
6. D=30, A=225*pi
7. D=14, A=49*pi
13. r^2=9/25, so r=3/5, so C=2*pi*3/5=6*pi/5
16. A=pi*r^2=pi*(2.5)^2=6.25*pi
20. area of the circle is 400*pi^2, area of the sector is 1/10 of that, so the degree measure is 1/10 of 360=36 degrees
21. area of circle=225*pi^2. to get side s of square, use fact that area of square is s^2, so s=sqrt(225*pi)^2=15*pi=47 ft
2006-10-02 13:10:35 · answer #2 · answered by James L 5 · 0⤊ 0⤋
Learn the basic:
if radius is given
Area of circle = Pir^2
if diameter is given
Area of circle = Pid^2/4
Finding the sector:
Sector = rtheta
Remember be careful with units used.
2006-10-02 13:09:13 · answer #3 · answered by The young Merlin 4 · 0⤊ 0⤋
Answer to 16th question is:
Formula for area of a circle is: 3,14 (pi number) x radius squared
So it is: 3,14 x 2,5 (squared) just calculate it....
Other formulas are:
for diametre = 2radius (So it is easy to solve 6th and 7th question)
2006-10-02 13:11:37 · answer #4 · answered by identity_letters 2 · 0⤊ 0⤋
Send the formulas too and I can send you the answers.
2006-10-02 13:05:35 · answer #5 · answered by stranger2ooo 3 · 0⤊ 0⤋
hey, i'm in geography so I dont want to think about it in my free time.
2006-10-02 13:04:55 · answer #6 · answered by Kek, the god of darkness 2 · 0⤊ 0⤋
Sorry Nine times, I haven't a clue............
2006-10-02 13:09:54 · answer #7 · answered by thomasrobinsonantonio 7 · 0⤊ 0⤋