WAEC - Mathematics (1990 - No. 30)
In the diagram above, WXYZ is a rhombus and ∠WYX = 20°. What is the value of ∠XZY
20o
30o
45o
60o
70o
설명
Diagonals bisect at 90°; < YXZ = 90° - 20° = 70°
But ZY = XY (sides of a rhombus)
\(\therefore\) < XYZ = 70° (base angle of an isos. triangle)