Answer: x + 2x + x-40 = 180
First angle= 55º
Second angle= 110º
Third angle= 15º
Step-by-step explanation: The sum of the angles of a triangle is 180º
Take the values given and use x as the unknown first angle. then create terms for the other two angles based on that:
The second angle of a triangle is double the first angle becomes 2x
The third angle is 40 less than the first angle becomes x-40
x + 2x + x-40 = 180 Solve by adding like terms . x + 2x + x = 4x
4x -40 = 180 Add 40 to both sides to "cancel" the -40 on the left
4x + 40 -40 = 180 + 40 becomes
4x = 220 Divide both sides by 4 to "cancel" the 4 on the left side
4x/4 = 220/4
x = 55 This is the first angle. Substitute 55 for the "x" in the original terms
2(55) = 110 The second angle
(55) -40 = 15 the third angle
