Kevin drew a triangle with angle measures of 30 degrees and 40 degrees and side measures of 5 cm, 7 cm, and 8 cm. Explain, using sides and angles, which type of triangle Kevin drew.
Kevin drew an acute triangle, since all three angles measure less than 90 degrees and all three side lengths are different.
BUT....
2angles are given, so the third angle is 110
checking for the smallest angle using the cosine law:
5^2 = 7^2 + 8^2 - 2(7)(8)cos theta
112cos theta = 88
theta = 38.2 degrees, which contradicts the data given in the problem.