Solve the resulting triangles if the given changes are made in the indicated examples of this section.

In Example 3, solve the triangle if 49.3 is changed to 54.3.

Data from Example 3

For a triangular roof truss with sides 49.3 ft, 21.6 ft, and 42.6 ft, find the angles between the sides. See Fig. 9.71.

First, we let the sides be a, b, and c, with opposite angles of A, B, and C. Then, because the longest side is 49.3 ft, we first solve for angle A. Because a² = b² + c² − 2bc cos A,

Now we can use the law of sines to find angle B:

Angle C can be found by subtracting from 180°: C =180° − 94.6° − 25.9° = 59.5°.

B 42.6 ft, 49.3 ft Fig. 9.71 A 21.6 ft.