Question

Here are two intersecting lines. Angle a measures 99 degrees. Find the measure of angles b and c.
Start by finding the measure of angle b.
a = 99ºbºcº

Angle b measures
99
degrees.
Nice!
What is the measure of angle c?
a = 99ºb = 99ºcº

Angle c measures
degrees.

Answer 1

When two lines intersect, they form two pairs of vertical angles.

Given that angle \( a \) measures 99 degrees and angle \( a \) is vertical to angle \( b \), angle \( b \) also measures 99 degrees.

To find the measure of angle \( c \), we can use the fact that the angles on a straight line add up to 180 degrees. Therefore:

\[
c = 180^\circ - a
\]

Substituting the value of angle \( a \):

\[
c = 180^\circ - 99^\circ = 81^\circ
\]

Thus, angle \( c \) measures 81 degrees.

To summarize:

- Angle \( a = 99^\circ \)
- Angle \( b = 99^\circ \)
- Angle \( c = 81^\circ \)