Page 153 - NUMINO Challenge_B2

Answer
Key

Shapes 2 First, draw a line that passes through the point

7 Angles p.60~p.61 where lines C and D intersect and that is parallel
to lines A and B. Mark all angles that have a
measure of 48° and 52°, and you get 48
52 180 . Therefore, the measure of angle is
180 (48 52 ) 80 .

Example 4 5 6

Example 30 , 60 A 52
alternate angle, corresponding angle
60 , 40 , 100 48

52 48
48 52

B

Type 7-1 Parallel Lines and Angles p.62~p.63

CD

1

122° 43° Type 7-2 Diagonals and Angles p.64~p.65
43°

122°

122° 43° 1 When parallel lines intersect another line, all the
alternate angles are equal. First, find the
122° alternate angle of angle . Then, find the
alternate angle of that angle.
122° 43°
43° AD

2 When you add 43 and the measure of angle ,
you get 180 . Therefore, 180 43 137 .

3 Since 122 43 180 ,

180 (122 43 ) 15

4 Angle Angle 15 137 152 BC

Problem solving 2 When you fold the square in half, the sum of
angles and is equal to the measure of
1 Since the sum of angle and 120 is 180 , the angle BDC, 90 2 45 .

measure of angle is 180 120 60 .

A

B
120

C

D

NUMINO Challenge B2