JAMB - Mathematics (2005 - No. 43)
in the diagram above, calculate the value of x.
60o
100o
120o
140o
설명
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).