Which of the following must be true? the diagram is not to scale. a) bc < fh b) ac = fh c) ab < bc d) ac < fh

Choice D

By the hinge theorem, we know that the opposite side of the given angles will be larger as you increase the angle. Basically think of a door opening. The greater or wide the door is open, the larger the hinge angle leading to a larger distance from door to frame. 

We see that angle G = 70 is larger than angle B = 28. So the opposite side HF must be larger than side AC

Note: the hinge theorem only works if we know two pairs of sides are congruent like this