#1**+1 **

BA=16 ft because if one angle is 90 and another one is 45, the triangle is equilateral, so the third angle is 45.

Pythagorean theorem: BC²=AB²+AC²

BC²=256+256

BC²=512

BC=√512=16√2 ft.

Why 16√2? To put "16" under √ you need 16*16=256. Then you need 16*2=√512. So √512=16√2.

vikkiry
Mar 28, 2017

#2**+1 **

1. We can sovle the first one using the Law of Cosines.......we need to find the angle opposite the greatest side

42^2 = 34^2 + 28^2 - 2 (34)(28)cos (theta)

cos (theta) = [ 42^2 - 34^2 - 28^2] / [ -2 * 34 * 28 ]

arccos ( [ 42^2 - 34^2 - 28^2] / [ -2 * 34 * 28 ] ) = theta ≈ 84.7°

Since the greatest angle lies opposite the greatest side, this triangle is acute

2. Since angle B = 45, then so does angle C.......and if two angles of a triangle are equal, then the sides opposite those angles are also equal......so CA = BA

CPhill
Mar 28, 2017