Felicia, a parent:
A rectangle whose base is twice its altitude is inscribed in a circle whose radius is 5 mm.
Find the area of the rectangle.
In my diagram I let a mm be the altitude of the rectangle. What is the length of the base?
Angle CAB is a right angle. What is the length of AB? What is the length of CA? What does Pythagoras theorem say for triangle CAB?
Solve for a.