Question

In △ABC, ∠A ≅ ∠C. If AB = 4x + 25, BC = 2x + 45, and AC = 3x − 15, determine the length of side AB.

Answer 1

• 65

Explanation:

If angles A and C are congruent, then opposite sides should be congruent as well:

• AB = BC
• 4x + 25 = 2x + 45
• 4x - 2x = 45 - 25
• 2x = 20
• x = 10

Then AB is:

• AB = 4x + 25
• AB = 4*10 + 25 = 65