Question

In a certain triangle, ∠B is double ∠A, and ∠C is triple ∠B. How big is ∠A? Show how you know.

Answer 1

Answer:

Great question...I will help you set this up for so that you will grasp the concept of these kinds of problems. However, I will not solve it for you...by understanding how to set these problems up and then answer them will make you a pro at knowing how to solve these problems.

Let's begin with what we know...we have a triangle ABC and obviously there are 3 angles inside ABC.

We know that when we add the angle together, it should equal 180°

That means; m∠A + m∠B + m∠C = 180° Right?!

Now lets label what your problem gives us:

m∠A measures something...we'll say: a so then m∠A = a

m∠B is twice as large as m∠A so then we can write 2 times a = 2a

m∠C measures 20° more than m∠A so we can write = (a + 20)

Going back to our equation we confirmed:

m∠A + m∠B + m∠C = 180°

Now...let's substitute what we know:

(a) + (2a) + ( a + 20) = 180°

Using the Associative Property of Algebra we re-write:

a + 2a + a + 20 = 180°

Re-write 2a + a + a + 20 = 180° or 4a + 20 = 180°

Answer 2

Answer:

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