This problem puzzles me. The instructions are to use the theorems that say "The largest/smallest angle is opposite the largest/smallest side", the Triangle Inequality Theorem (2 sides of a triangle added together are greater than the 3rd side), and the Exterior Angle Inequality Theorem, which is...

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The measure of an exterior angle of a triangle is greater than the measure of either of the nonadjacent interior angles.

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And using any combination of those theorems, we need to explain why the diagram is incorrect.

I came up with the following...

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According to the Exterior Angle Inequality Theorem, the exterior angle E can't be congruent to angle D as indicated because the measure of angle E is supposed to be greater than either of the nonadjacent interior angles.

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Is that sufficient reasoning? What do you say?

If you feel like helping me with just 1 more, I'd appreciate it. Just PM me.

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"Last night I tried to slip it in her rear. When she began to
complain about the pain, I stupidly told her to take it like a man."

~Quantumleaper