Δ ABC is isosceles. Angles B and C are congruent. The m∠A = 40°, m∠B = (3x + 1)°. Find x.

A) 13
B) 23
C) 46.3
D) 70

Respuesta :

Answer: Option 'B' is correct.

Step-by-step explanation:

Since we have given that

ΔABC is an isosceles and ∠B and ∠C are congruent.

So, ∠B=∠C=3x+1

∠A= [tex]40\textdegree[/tex]

As we know the formula for "Sum of three angles in a triangle ":

[tex]\angle A+\angle B+\angle C=180\textdegree\\\\40\texdegree+3x+1+3x+1=180\textdegree\\\\42\textdegree+6x=180\textdegree\\\\6x=180\textdegree-42\textdegree\\\\6x=138\textdegree\\\\x=\frac{138}{6}\\\\x=23\textdegree[/tex]

Hence, Option 'B' is correct.