Answer:
x=13
Step-by-step explanation:
all triangles add up to 180 so set equal to 180
77+90+x=180
solve for x
x = 13
90 + 77 + x = 180
90 + 77 = 167
180 - 167 = 13
Plz mark as brainliest if correct! Have a nice day!!!
-Lil G
