Answer:
m<ABC = 71°
Step-by-step explanation:
Given:
m<BCA = 71°
x = 31 cm
y = 50 cm
Required:
m<ABC
Solution:
First, find AB, using Cosine Rule:
AB² = x² + y² - 2xy*Cos m<ABC
Plug in the values
AB² = 31² + 50² - 2(31)(50)*cos 71
AB² = 3,461 - 1,009.26128
AB² = 2,451.73872
AB = √2,451.73872
AB = 49.5150353 ≈ 50 cm
✔️Since AB ≈ 50 cm, and AC is also 50 cm, it means the triangle is an isosceles triangle.
Therefore, the base angles of ∆ABC, <ABC and <BCA, would be congruent.
Therefore,
m<BCA = m<ABC = 71°
m<ABC = 71°
