JAMB - Mathematics (2005 - No. 43)

in the diagram above, calculate the value of x.

60^o

100^o

120^o

140^o

FROM the diagram above

100 + a = 180 (sum of angles on a straight line)

a = 180 - 100 = 80º

Z = 80 + 40 = 120º (exterior angles of a triangle = sum of the two opp. interior angles)

Z = x = 120º (corresponding angles are equal).