Finding Angle ABC: Geometric Construction with 100° Angle DBC

Question

Determine the size of angle ABC?

DBC = 100°

00:00 Find angle ABC

00:03 The angle is the angle at point B between letters A and C

00:09 This is the size of the angle according to the given data

00:12 And this is the solution to the question

We can see from the diagram that angle DBC equals 100 degrees.

We can also see that the size of angle ABC is shown and equals 40 degrees.

Therefore, the answer is 40.