The missing angle in the triangle of the left is:
51 + 74 + x = 180
x = 180 - 51 - 74
x = 55°
The missing angle in the triangle of the right is:
55 + 74 + x = 180
x = 180 - 55 - 74
x = 51°
Then, both triangles are similar. This means that their corresponding sides are in proportion. These sides are:
35 in