Question: CHAPTER 2 1
Geometry
Lines and Angles
DIRECTIONS: Find the value of each expression in degrees.
For A through E, use the following figure:
A. what is the measure of \(\angle a\) ?
B. what is the measure of \(b\) ?
C. what is the measure of \(c + d\) ?
D. what is the measure of \(e\) ?
E. What is the measure of \(2c + 3f\) ?
position_hint: top-right
A line labeled \(p\) slopes down from left to right and intersects the top horizontal line at an angle marked \(40^\circ\); nearby are angles \(a\) and \(b\) on the first and second horizontal lines, with \(c\) on the right-side diagonal intersection on the second horizontal line, and a small right-angle marker at the lower central intersection where lines \(m\), \(n\), and the diagonal lines meet; another diagonal labeled \(q\) intersects the top line with angles \(f\) and \(g\), and the bottom cluster has angles \(d\) and \(e\) around the intersection.
1. **State the problem:** We need to find the measures of angles \(a\), \(b\), \(c + d\), \(e\), and \(2c + 3f\) in degrees based on the given figure with lines and angles.
2. **Given information:**
- Angle at the intersection of line \(p\) with the top horizontal line is \(40^\circ\).
- There is a right angle (\(90^\circ\)) at the lower central intersection.
3. **Find \(a\):**
- Since \(p\) intersects the top horizontal line at \(40^\circ\), and \(a\) is the adjacent angle on the straight line, angles \(a\) and \(40^\circ\) are supplementary.
- Use the supplementary angle rule: $$a + 40 = 180$$
- Solve for \(a\): $$a = 180 - 40 = 140$$
4. **Find \(b\):**
- \(a\) and \(b\) are corresponding angles formed by parallel lines and a transversal, so \(b = a = 140\).
5. **Find \(c + d\):**
- The right angle marker indicates \(c + d = 90^\circ\).
6. **Find \(e\):**
- \(e\) and \(d\) are complementary to the right angle, so \(e = 90 - d\).
- Since \(c + d = 90\), then \(d = 90 - c\).
- Substitute \(d\) into \(e = 90 - d\): $$e = 90 - (90 - c) = c$$
7. **Find \(2c + 3f\):**
- \(f\) is vertically opposite to the \(40^\circ\) angle, so \(f = 40\).
- Calculate: $$2c + 3f = 2c + 3 \times 40 = 2c + 120$$
**Final answers:**
- \(a = 140^\circ\)
- \(b = 140^\circ\)
- \(c + d = 90^\circ\)
- \(e = c\)
- \(2c + 3f = 2c + 120\)