Answer:
80
Step-by-step explanation:
The three angles of a triangle add to 180 degrees. One angle is 10, the second is a right angle( which is 90 degrees). Let the third angle be x
10 +90 +x = 180
Combine like terms
100 +x =180
Subtract 100 from each side
100-100 +x= 180-100
x = 80
