SOLUTION: in isosceles triangle ABC, angle C is the vertex angle. If measure angle A is 3x + 5 and mesaure angle C = 2x, find the measure of angle B.

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Question 1052475: in isosceles triangle ABC, angle C is the vertex angle. If measure angle A is 3x + 5 and mesaure angle C = 2x, find the measure of angle B.
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52765) About Me  (Show Source):
You can put this solution on YOUR website!
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in isosceles triangle ABC, angle C is the vertex angle. If measure angle A is 3x + 5 and mesaure angle C = 2x, find the measure of angle B.
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If I do understand the condition correctly, then the angles A and B are base angles.
Then they are congruent and have the measure of 3x+5 each.

So, you have an equation 

(3x+5) + (3x+5) + 2x = 180.   (the sum of interior angles of a triangle . . . ).

Simplify and solve it for x.

For many other solved similar problems see the lesson
    - Solved problems on angles of a triangle
in this site.

You have this free of charge online textbook on Geometry
    - GEOMETRY - YOUR ONLINE TEXTBOOK
in this site.

The referred lesson is the part of this textbook in the section "Introductory Geometry problems"
under the topic "Finding angles of triangles, parallelograms and rectangles".


Answer by josgarithmetic(39615) About Me  (Show Source):
You can put this solution on YOUR website!
system%282%283x%2B5%29%2B2x=180%2CSolveItandthen%2C3x%2B5%29

Angle B will also be 3x+5.