Formulas for a circle Flashcards
1
Q
How do you calculate the length of an arc?
A
The length of an arc =
θ/360 x 2πr
θ = angle | r = radius
circumference = 2πr of πd, so the formula calculates a fraction of the circumference.
2
Q
What is the formula used to calculate the area of a segment?
A
Area of a segment =
θ/360 x πr² - 1/2r²Sinθ
This is because, a segment is part of a circle with a triangle removed, so this is the area of a fraction of a circle, minus the triangle, hence we subtract 1/2 absinθ, in the form 1/2r²Sinθ.
3
Q
What is the formula used to calculate the area of a sector?
A
θ/360 x πr²
This is just a fraction of the area of a circle.
