Answer:
w=60°
Step-by-step explanation:
triangle=180°
angle on a straight line=180°
using that,
we need to find the angle on the same line with that of "w+20°" angle, so we name it as "X"
so, 180-(w+20)=X
expand bracket by multiplying it with the "-"
so it'll be: 180-w-20=X
then rearrange to get like terms together
180-20-w=x
160-w=x
so the missing angle in the triangle is now (160-w)°
now using the angles in a triangle =180°
we add all the angles and equate it to 180, so:
w-30+w-10+160-w=180°
collect like terms again:
w+w-w-30-10+160=180
2w-w+120=180
w+120=180
move 120 to the other side and remember the sign changes, so:
w=180-120
therefore w=60°
now you can substitute w=60 into the triangle and see you'll get 180°
hope that helps
