Question: Find m\angle G in parallelogram EFGH.
H
E
2c+9^\circ
G
F
c
m\angle G =
1. **State the problem:** We need to find the measure of angle $G$ in parallelogram $EFGH$ given that $m\angle E = 2c + 9^\circ$ and $m\angle F = c$.
2. **Recall properties of parallelograms:** Opposite angles are equal, and adjacent angles are supplementary (sum to $180^\circ$).
3. **Use the supplementary angle rule:** Since $E$ and $F$ are adjacent angles,
$$m\angle E + m\angle F = 180^\circ$$
Substitute the given expressions:
$$2c + 9 + c = 180$$
4. **Simplify and solve for $c$:**
$$3c + 9 = 180$$
$$3c = 180 - 9$$
$$3c = 171$$
$$c = \frac{171}{3}$$
$$c = 57$$
5. **Find $m\angle E$ and $m\angle F$:**
$$m\angle E = 2c + 9 = 2(57) + 9 = 114 + 9 = 123^\circ$$
$$m\angle F = c = 57^\circ$$
6. **Find $m\angle G$:** Opposite angles in a parallelogram are equal, so
$$m\angle G = m\angle E = 123^\circ$$
**Final answer:**
$$m\angle G = 123^\circ$$