Answer:
x2 + y2 = r2, and this is the equation of a circle of radius r whose center is the origin O(0, 0). The equation of a circle of radius r and center the origin is x2 + y2 = r2.
I think this is the answer.
Complement angles, sum is equal 90
Give one angle = 70 to find other: 90 - 70 = 20
Answer
Complement of angle with the measure of 70 degrees is 20 degrees