Question

In triangle ABC angle B is 5 times angle A and angle C is 8 less than 4 times angle A what is the size of angle A?

Answer 1

Angle A: a

Angle B: 5a

Angle C: 4a-5

 

Now, to find the value of a, we need to remember that all the angles in a triangle add up to 180 degrees.  

 

So we have:   a+5a+4a-5 = 180

 

We can solve that equation by combining like terms to get: 10a-5=180

 

We can add 5 to both sides:  10a =185

 

And divide by 10:  a = 18.5

 

That tells us the measure of angle A!  (It's 18.5 degrees).  Now we can go back and find B by multiplying A by 5.  We get 92.5 degrees for that.  

 

Finally, we can find C by taking 4*18.5-5.  We get 69 degrees for that.  

 

One last thing-- let's check that they really do add up to 180!  69+92.5+18.5 = 180.  Yep!  

 

Hope that helps you!