4.That first one sounds familiar; I think I did it yesterday.
The sides don't matter (except that they're equal) so the base angle b satisfies
b + b + 38 = 180
2b = 142
b = 71
Choice a
5.
42 + 42 + v = 180
v = 180 - 84 = 96
choice d
6. That's three acute angles, an acute triangle
7. We need to satisfy the triangle inequality which means the sum of the two smaller sides needs to be bigger than the largest
10+15>24 so choice b
8.
SRT = RTS = 180 - STU
3x - 50 = 180 - 7x
10 x = 230
x = 23
choice a
