In the diagram, ∠ABC and ∠BCD are right angles, ∠BAD = t and ∠EDF = 70°. Find the value of t.
Attached Figure / Diagram
A
70°
B
165°
C
140°
D
110°
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
Vertically opp angles are equal ∠CDE = 70^\circ
Sum of interior angles in a quadilateral = 360^\circ
(90 + 90 + 70 + t)^\circ = 360^\circ
t^\circ = 360^\circ - 250^\circ
t^\circ = 110^\circ
Source: WAEC / JAMB / NECO Classroom Archive (Record #61196)