# Angle Addition Postulate

Activity

## Drag the points A, B, C and D in the sketch below

## Determine whether the following statement is always, sometimes, or never true.

**D is in the interior of ∠ABC**

## Determine whether the following statement is always, sometimes, or never

**m∠ABD + m∠DBC = m∠ABC**

**If D is in the interior of ∠ABC , m∠ABC=123° and m∠ABD=55°. Find m∠CBD**

**If m∠ABD=130° and m∠ABC=50°. Find m∠DBC**