Five congruent circles are placed with their centers equally spaced and collinear as shown. A line connects the bottom of the first circle and the top of the fifth circle. The area under the line enclosed by the circles, shown in yellow, is equal to 40. The overlapping area between two circles is 5.
What is the area of a single circle?

A circle has diameter AB. A line starts at A and zig-zags exactly 4 times between the diameter and the circumference until it ends at B, as shown below.

If each of the angles the line makes with the diameter has the same measure α, what is α equal to?

A triangle is divided by 8 parallel lines that are equally spaced, as shown below. Starting from the top small triangle, color each alternate stripe in blue and color the remaining stripes in red. If the blue stripes have a total area of 145, what is the total area of the red stripes?

Thirty equally spaced points on the circumference of a circle are labelled in order with the numbers 1 to 30. Which number is diametrically opposite to 7?

Construct a square. Construct 4 semicircles, each with diameter spanning the center of the circle to a corner of the square and whose arc is counterclockwise from its diameter. Shade in blue the region exterior to the square but interior to the semicircles and interior to the square but exterior to the semicircles, as shown below. If the square has a side length equal to 4,
what is the area shaded in blue?