Practice and the Chapter III test
Answers are for parents and teachers.
1
What is the circumference of the circle circumscribed about a square of side 4?
4√2π
2
A 45° sector is cut from a disc of radius 4. What is the area of the rest?
14π
3
What is the area of the disc circumscribed about a right triangle with legs 6 and 8?
25π
4
An arc of 135° of a circle has length 6π. Find the radius R.
8
5
Why does the combined area of equal-radius sectors at the vertices of a triangle depend on the sum of its angles?
The sector angles add up to 180°, so together they equal a half-disc.