Open Middle®

Equation of a Circle 2

Directions: Using the digits 1 to 9, at most two times each, place a digit in each box to make a circle with the least possible area.

How do we ensure that the digits we choose create a circle? How do the digits we choose affect the size of our circle?

The least possible area we can have comes from the equation 9x² + 9y² = 1 for an area of ~0.35 units².

Directions: Using the digits 0 to 9, at most one time each, place a digit …