if a semi-circle has the diameter of 12cm find its perimeter .let that little (pi) sign = 3
thanxs
2007-05-16 01:29:25 · 9 answers · asked by jess y 4 in Science & Mathematics ➔ Mathematics
A full circle has a circumference of pi times diameter.
You have a half-circle, which is half the circumference of the full circle, plus a line across the diameter, to close the shape. (Perimeter is the distance around the entire semicircle shape, not just the curved part -- if the question were for that measure, it would ask for for arc length.)
perimeter = (pi * diameter)/2 + diameter
using 12cm for the diameter and 3 for pi:
perimeter = (3* 12cm)/2 + 12cm
perimeter = 18cm + 12cm
perimeter = 30cm
2007-05-16 01:33:25 · answer #1 · answered by McFate 7 · 2⤊ 0⤋
Perimeter P of semi-circle = 1/2 circumference of circle + diameter D = 1/2 * pi * D + D = (1/2 * pi + 1)D
Plug in pi = 3 and D = 12,
P = (1/2 * 3 + 1)(12) = 30 cm
2007-05-16 02:02:27 · answer #2 · answered by Loong 2 · 1⤊ 0⤋
So, a semi-circle is half of a full circle. Now, the perimeter (or circumference) of a circle is defined as pi*d. So the perimeter of a semi-circle is pi*d/2 = (3*12)/2 = 36/2 = 18 cm
Now, you have to add in the diameter itself. So 18 + 12 = 30 cm
2007-05-16 01:53:47 · answer #3 · answered by Anonymous · 1⤊ 0⤋
diameter = 12cm
length of semicircle = pid/2 = 6pi
so perimter = 12+6pi( sum of)
if pi =3 perimeter = 12 + 6*3 or 30 cm
2007-05-16 01:34:23 · answer #4 · answered by Mein Hoon Na 7 · 1⤊ 0⤋
the perimeter of a circle is also caled circumference
the formula is
c=pi*d
c=3*12 cm
c=36cm
since it is semi circle divide it by 2
=18cm
+no need to add for diameter=)
+the circumference is the perimeter itself...
2007-05-16 02:54:38 · answer #5 · answered by itlog 2 · 0⤊ 1⤋
3.14 x 12 = 37.68
37.68 divided by 2 = 18.84
18.84 + 12 = 30.84
so your answer is 30.84
if you are using 3 as pi then..
3 x 12 = 36
36 divided by 2 = 18
18 + 12 = 30
so your answer is 30
2007-05-16 01:37:29 · answer #6 · answered by Anonymous · 1⤊ 0⤋
3. 80x 4. 80x + a million 5. 250(80x + a million) 6. 250(80x + a million) + y 7. 250(80x + a million) + 2y 8. 250(80x + a million) + 2y - 250 9. [250(80x + a million) + 2y - 250] / 2 = [20000x + 250 + 2y - 250] / 2 = [20000x + 2y] / 2 = 10000x + y
2016-12-29 06:37:25 · answer #7 · answered by Anonymous · 0⤊ 0⤋
r=6
pi*r=6*3=18
2007-05-16 02:34:39 · answer #8 · answered by receb a 2 · 0⤊ 1⤋
12x3
36 divide by 2 since its half
= 18 cm
2007-05-16 03:06:22 · answer #9 · answered by bigdaddy 1 · 0⤊ 1⤋