Question

3
Calculate the angles marked with small letters in the following diagrams.​

Answer 1

Answer:

Since diagonal of rectangle bisect at 90°.

So In ∆AOB,

OAB+ABO+AOB=180° (angles)

21°+ABO+90°=180°

ABO=180-111=69°

ABC=x+ABO=90°

x=90°-69=21°