The side across from the 63° angle is 299.5 ft and the side across from the 56° angle is 278.7 ft.
We will use the Law of Sines to solve this. First, the angle across from the 63° angle:
sin 61/294 = sin 63/x
Cross multiply:
x*sin 61 = 294 sin 63
Divide by sin 61:
(x sin 61)/(sin 61) = (294 sin 63)/(sin 61)
x = 299.5
For the side across from the 56° angle:
sin 61/294 = sin 56/x
Cross multiply:
x*sin 61 = 294 sin 56
Divide both sides by sin 61:
(x sin 61)/(sin 61) = (294 sin 56)/(sin 61)
x = 278.7