I need to know the value of x and y.

Thanks!

I need to know the value of x and y.

Thanks!

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This looks more complicated than it is.

Facts: An Isoscles triangle has 2 angles of the same measure.

Sum of the angles of a triangle = 180.

What's up with the chopped angle (2y + 20)?

It's distracting, just call it @.

Look at your equation as:

x+120+@ = 180

because 2 angles have to be the same, either @ is 120 or @ is x.

@ is not 120, because 120+120=240 which is over 180.

Foul ball.

So @=x

making the equation :

x+120+x=180

2x+120=180

2x=60

x=30

think back to your substitution

@ = x

so @ = 30

so your distracting, chopped angle 2y+20=30

2y=10

y=5

done.

Solve for x first,

x+120+x=180

x = 30 degrees

Solve for y,

2y+20 = x = 30

y = 5 degrees

The sum of the 3 angles in the triangle is 180 degrees. We already know that an angle of the triangle measures 120. In an isosceles triangle, two angles have the same measures and each of those two angles measures less than 90. This simply means that x=2y+20, when we do substitution,

we have x+120+x=180

2x+120=180

x=30

y=(x-20)/2

y=5

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## Comments

An isosceles triangle has two angles with the same measure. Are the angles x, 2y+20, and 120? I know that the three angles add up to 180.

two angles with the same measure:<a, <c; <a=x <c=2y+20

<b=120; I need to know the value of x and y