Question

An acute triangle has side lengths 21 cm, x cm, and 2x cm. If 21 is one of the shorter sides of the triangle, what is the greatest possible length of the longest side, rounded to the nearest tenth?

Answer 1

Answer: C. 42.0 cm

Step-by-step explanation: I just took the test

Answer 2

The triangle inequality requires the sum of the two short sides be at least as long as the longest side.
.. 21 +x ≥ 2x
.. 21 ≥ x
.. 42 ≥ 2x

The largest possible length of the longest side is 42 cm.