Question

In triangle ABC, m∠ABC = (4x – 12)° and m∠ACB = (2x + 26)°. Yin says that if x = 19, the triangle must be equilateral. Is he correct? Justify your answer.

Answer 1

Answer:

Yes

Step-by-step explanation:

If x = 19

Then < ABC =

$4 \times 19 - 12 \\ = 76 - 12 = 64$

< ACB =

$2 \times 19 + 26 \\ = 38 + 26 = 64$

So < ABC = < ACB

Therefore the triangle is equilateral.