Problem:

Kali measured the angles in a triangle and reports that the angles measure 45, 65, and 90 degrees.

Explain how you know that Kali made measurement errors.

Answer:

The sum of the angles of a triangle is 180 degrees. 

The sum of the angles Kali measured is 200 degrees so she made errors when measuring.

or

Since one of the angles is a right angle, the sum of the other two angles must be 90 degrees. 

Since 45 + 65 = 110, Kali made an error when measuring.