Question

What is the value of y? Enter your answer in the box.

Answer 1

Answer:

$y=20^o$

Step-by-step explanation:

We can see from our given triangle that it has two equal sides. This means that the angles corresponding to these sides will be of equal measure.

$m\angle C=m\angle B$  

Upon substituting our given values we will get,

$m\angle C=25^o$

Since the measure of all the angles of a triangle is 180 degrees.

$m\angle A+m\angle B+m\angle C=180^o$

Now let us substitute the measures of our given angles.

$3y+70+25+25=180$

$3y+120=180$

$3y+120-120=180-120$

$3y=60$

Let us divide both sides of our equation by 3.

$\frac{3y}{3}=\frac{60}{3}$

$y=20$

Therefore, the value of y is 20 degrees.

Answer 2

You must know that the sum of interior angles is 180°. We also know that AC and BA are congruent which means angles B and C are also congruent. To find x we can assume 25=5x. Which makes x=5, and angle C=25°.

Then we can add all the angles to find y and A. 25+25+(3y+70)=180. Then solve for y and then solve for angle A.