Answer:
The answer is d.
Step-by-step explanation:
As we know, sin x= cos (90°-x)
sin 18° = cos (90°-18°)
= cos 72°.
Similarly, sin 72°= cos (90°-72°)
= cos 18°
But, sin 55°= cos (90°-55°)
= cos 35°
120°
Opposite angles in a cross of 2 lines like this are equal;
A = 120 and B = D = 60°
