To find measurements that don't make up a triangle, you need to find the measurements that don't make up 180 degrees, or on the three sides on the measurements, do not have A + B > C.
All triangle sides together make up 180 degrees. So we need to add up all of the angle measurements and find the ones, or we need to find A + B > C. When we find one that doesn't have these two things, it isn't a triangle.
A. 10° + 25° + 145° = 180° (this is a triangle)
B. 9m + 15m > 9m (this is a triangle)
C. 40° + 70° + 65° = 175° (this is not a triangle)
D. 6cm + 8cm > 10cm (this is a triangle)
The answer is C. because the answer is 175° which is less than 180°.
