SOLUTION: Could someone please help me ? Triangle ABC: angle B is 5 times angle A and angle C is 18 degrees than 4 times angle A Find the size of the angles

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Question 422823: Could someone please help me ? Triangle ABC: angle B is 5 times angle A and angle C is 18 degrees than 4 times angle A Find the size of the angles
Answer by htmentor(1343) About Me  (Show Source):
You can put this solution on YOUR website!
First of all, we know the sum of all the angles in a triangle is 180 degrees:
1) A + B + C = 180
Since angle B is 5 times angle A we have:
2) B = 5A
And angle C is 18 (less or more? --not given in problem--assume more!) than 4 times angle A:
3) C = 4A + 18
We need to solve this system of equations.
Putting the value for B in 2) into 1) gives:
A + 5A + C = 180 -> 6A + C = 180.
Now solve for C and insert this value in equation 3):
C = 180 - 6A -> 180 - 6A = 4A + 18
Solve for A:
10A = 162 or A = 16.2 deg.
So B = 5*16.2 = 81 deg.
Therefore C = 4*16.2 + 18 = 82.8 deg.