Answer:
99°
Step-by-step explanation:
Internal Angles of triangles ALWAYS add up to 180°
So, 180° is our total.
We can form an equation. x° + 55° + (4x - 5)° = 180°
We can remove the brackets to form; x° + 55° + 4x° - 5° = 180°
We can get rid of the like terms by either adding or subtracting them.
x° + 4x° + 55° - 5° = 180°
5x° + 50° = 180°
We can then subtract 50° from both sides.
5x° = 180° - 50°
5x° = 130°
We then make x the subject and divide both sides by 5°
x = 26
x was our unknown so where there is x we put 26
The angle on the far left is simply 26°
The other angle, (4x-5)° becomes (4(26) - 5)°
If you simplify that, you get (104-5)°
Hence the last angle was 99°
If you want to ensure that your answer is correct, simply add the angles. They should always add up to 180° if you're working with a triangle
55° + 26° + 99° = 180°
