Exercise 3 Page 607

Exploration 1(e)

Our conclusion tells us that when two sides of a triangle are congruent, the base angles are congruent. To prove this, you can use a ruler to construct an isosceles triangle.

Next, we should use a protractor to measure the base angles.

Both angles show a measure of $45^{\circ },$ which means they are congruent. You can draw as many of these triangles as you want until you have removed all doubt that the base angles are congruent when two sides are congruent.

Exploration 1(f)

Our conclusion tells us that when the base angles of a triangle are equal, the sides opposite them are congruent. To prove this, you can use a protractor to construct two congruent angles and the included side.

Next, use a ruler to connect the dotted lines and measure their lengths.

You can draw as many of these triangles as you want until you have removed all doubt that the legs are congruent.