In the figure, angle e measures 54° and angle g measures 29°. what is the measurement of angle h?

From the figure, you can say that angle E is equal to angle C because they both are vertically opposite. So, you can find angle D by substracting angle E and D from 360° (sum of angles at a point) and dividing the answer by two:
360°-54°-54° = 252°
252°÷2 = 126°
Then, you can find angle H by substracting the values of angle G and angle D from 180° (sum of angles in a triangle):
180°-126°-29° = 25°
Therefore, the answer is 25°.
I hope this answered your question :)