Question

Suppose a triangle has sides a, b, and c, and the angle opposite the side of length b obtuse. What must be true?​

Answer 1

C.

Explanation:

In triangles, the largest angle is always opposite from the longest side.

In other words, since the angle opposite to side b is obtuse and there are only 180 degrees in a triangle, then side b must be the longest side.

In an obtuse triangle, the longest side squared will always be greater than the squared values of the two shorter sides.

The correct answer is C.

Answer 2

C

Explanation:

If the angle opposite b is the obtuse angle then the answer is a² + c² < b² because in an obtuse triangle, the sum of the squares of the shortest sides must be less than the square of the longest side. In this case, the longest side is the one opposite the largest angle, which is b.