Lesson 14

For each triangle, find the measure of the missing angle.

Is there a triangle with two right angles? Explain your reasoning.

In this diagram, lines $AB$ and $CD$ are parallel.

Angle $ABC$ measures $35^\circ$ and angle $BAC$ measures $115^\circ$.

1. What is $m{\angle ACE}$?
2. What is $m{\angle DCB}$?
3. What is $m{\angle ACB}$?

Here is a diagram of triangle $DEF$.

1. Find the measures of angles $q$, $r$, and $s$.
2. Find the sum of the measures of angles $q$, $r$, and $s$.

3. What do you notice about these three angles?

The two figures are congruent.

1. Label the points $A’$, $B’$ and $C’$ that correspond to $A$, $B$, and $C$ in the figure on the right.

   

   

2. If segment $AB$ measures 2 cm, how long is segment $A’B’$? Explain.
3. The point $D$ is shown in addition to $A$ and $C$. How can you find the point $D’$ that corresponds to $D$? Explain your reasoning.