Answer:
Step-by-step explanation:
<2 + <1 + 20 = 180 A straight line has 180 degrees.
<2 is given as 90 degrees.
90 + <1 + 20 = 180 Combine like terms
<1 + 110 = 180 Subtract 110 from both sides
<1 = 180 - 110
<1 = 70
<1 + <2 + <3 = 180
<1 = 70
<2 = 90
70 + 90 + <3 = 180
160 + <3 = 180 Subtract 160 from both sides
<3 = 180 - 160
<3 = 20
20 + 20 + <4 = 180 Straight line theorem stated above.
40 + <4 = 180 Subtract 40 from both sides
<4 = 180 - 40
<4 = 140
