Page 270 - NUMINO_WB_6B
P. 270
125_G6U27_WB˜ ˙—» ¿º 2011.6.23 3:44 PM ˘ ` 24
125-S1-2
2. The following are the methods of finding the sum for exterior angles of a
triangle. Use the same method to find the sum of the exterior angles of a
quadrilateral and pentagon, and solve for x.
Sum of angles of extension lines of each
a segment: 180 3 540
Sum of exterior angles of a triangle:
b c 540 ( a b c) 540 180 360
a.
Sum of angles of extension lines of each
segment:
Sum of exterior angles of a quadrilateral:
b.
Sum of angles of extension lines of each
segment:
Sum of exterior angles of a pentagon:
c. 68 x
x 55
72 83
125-S1-2
2. The following are the methods of finding the sum for exterior angles of a
triangle. Use the same method to find the sum of the exterior angles of a
quadrilateral and pentagon, and solve for x.
Sum of angles of extension lines of each
a segment: 180 3 540
Sum of exterior angles of a triangle:
b c 540 ( a b c) 540 180 360
a.
Sum of angles of extension lines of each
segment:
Sum of exterior angles of a quadrilateral:
b.
Sum of angles of extension lines of each
segment:
Sum of exterior angles of a pentagon:
c. 68 x
x 55
72 83
