Directions: Using the digits 1-9, at most one time each, to fill in the blanks. Then solve the problem for x. Choose numbers such that the solution for x is a whole number.
Can you write an equation to represent the sum of the two unknown angles?
Top angle is 4x and bottom angle is 6x + 25.
x = 10 solves the problem.
Extension/extra challenge 1: set a value for x and find all the ways to make the problem have that solution.
Extension/extra challenge 2: change the value of the bottom right angle.
Source: Franco D. Adkins