How do you calculate the perimeter of a half circle?
perimeter of circle = pi*diameter OR
2*pi*radius.
http://math.about.com/od/formulas/ss/areaperimeter_5.htm
The question says that the diameter is 8 cm, and then it asks to fnd the perimeter. I found the answer using your formula but when I checked the back of the book, it said the answer was 20.56 cm, not 25.12 cm.
My calculator says 3.14159*8.00 = 25.13274 which rounds to 25.13 cm. The answer in the book must be wrong. Even if we rounded the pi number to 3.0 that x 8 = 24 cm.
Okay. Thank you very much. I had a feeling that the answer at the back was wrong, I tried many solutions, and it didn't work. So you're probably right. :)
To calculate the perimeter of a half circle, you need to know the radius of the half circle. The radius is the distance from the center of the circle to any point on its circumference.
To find the perimeter, you need to calculate the length of the curved part of the half circle, called the arc length, and add it to the diameter of the half circle.
Here are the steps to find the perimeter of a half circle:
1. Find the radius (r): Measure the distance from the center of the half circle to any point on its circumference.
2. Calculate the arc length (L): The arc length of a half circle is half the circumference of the full circle. The formula to calculate the circumference of a full circle is C = 2πr, where π (pi) is a mathematical constant approximately equal to 3.14159. Thus, the arc length of a half circle is L = (1/2) * 2πr = πr.
3. Calculate the diameter (d): The diameter is the distance across the widest part of the circle. In a half circle, the diameter is twice the radius, so d = 2r.
4. Calculate the perimeter (P): Add the arc length (L) to the diameter (d) to get the perimeter of the half circle. P = L + d = πr + 2r = r(π + 2).
By following these steps and plugging in the value of the radius, you can calculate the perimeter of any half circle.