All the measures in a triangle are equal to 180 degrees.
Let the unknown angle= x.
40+89+x= 180
Combine like terms.
129+x= 180
Subtract 129 from both sides.
x= 51
The angle is equal to 51.
I hope this helps!
~kaikers
Convert the larger unit into the smaller unit, and then solve.
I belive what you did wrong is that you didint show your work so what you have to do is explain how to do the problem with equations or explain in word form if i were you i would show my work in equations if you need help on how to set it up contact me.