Question

A) work out the size of angle x
b) give reasons for your answer

Answer 1

angle B=100 degrees

vertically opposite angle

angle B +x= 180 degree

100-180=x

80 degree =x

Answer 2

x = 80°

Explanation:

GIVEN :-

• AD ║ EH
• CG as transversal
• ∠CBD = 100°
• ∠EFB = x°

TO FIND :-

• The measure of x°

PROCEDURE :-

∠CBD + ∠FBD = 180° (∵ ∠CBD & ∠FBD form a linear pair )

⇒ ∠FBD = 180° - 100° = 80°

Also,

∠FBD = ∠EFB (∵ Alternative Interior Angles are equal )

⇒ x = 80°