standard_description: (+)Derive the equations of ellipses and hyperbolas given the foci, using the fact that the sum or difference of distances from the foci is constant.
problem_activity: Task
The goal of this task is to estimate the measure of angles in triangles with integer side lengths.
What are the angle measures in a triangle whose three sides each have length of one unit?  Explain.
What are the approximate measures of the three angles in a triangle whose side lengths are 3, 4, and 5 units respectively? Explain.
What are the approximate angle measures of the three angles in a triangle whose side lengths are 2, 3, and 4 units respectively?


aligns: no