Question

A problem asks to find the unknown side lengths and angle measures of a triangle with mZA = 130°, a = 54, and b = 59. Eva states that there are two possible triangles because h < a < b. Is Eva correct? Explain your reasoning.

If Eva is not correct, state how many possible triangles there are.

Answer 1

Explanation:

Eva is not correct. There is only one possible triangle that can be formed with the given information. This is because in a triangle, the length of any side must be less than the sum of the lengths of the other two sides.

Using the Law of Cosines, we can find the length of the unknown side, c:

c^2 = a^2 + b^2 - 2ab cos(ZA)

c^2 = 54^2 + 59^2 - 2(54)(59) cos(130°)

c ≈ 31.28

Since h < a < b, we know that h < 54 < 59. Therefore, the length of side c must be between 5 and 113 (59 - 54 and 59 + 54). Since c = 31.28 is between 5 and 113, it satisfies the triangle inequality and a triangle can be formed.

To find the measures of the other angles, we can use the Law of Sines:

sin(A)/a = sin(ZA)/c

sin(A) = (a/c)sin(ZA)

sin(A) = (54/31.28)sin(130°)

sin(A) ≈ 0.879

A ≈ 62.6°

Similarly,

sin(B)/b = sin(ZA)/c

sin(B) = (b/c)sin(ZA)

sin(B) = (59/31.28)sin(130°)

sin(B) ≈ 0.841

B ≈ 56.2°

Therefore, the measures of the three angles are approximately 62.6°, 56.2°, and 61.2°, and there is only one possible triangle that can be formed with these side lengths and angle measures.