Respuesta :

All of the angles in a triangle add up to 180 so you can set this equation up:
2x - 10 + x + 30 + 70 = 180

Now combine lie terms.
3x + 90 = 180

Subtract 90 from both sides.
3x = 90

Now divide three from both sides to get x.
x = 30

Now you know x so plug it into angle A to get the answer
2 (30) - 10
60 - 10
50

50 is the value of angle A!

Hope that helps! Let me know if you have any questions!

- mathwizzard3
if X = 30 then 30 x 2 - 10 = 50
here hope this helps
Ver imagen KurdishPotato