Find Angle ABC in a Rectangle with 30-Degree Reference Angle

Question

ABCD is a rectangle.

$∢\text{ABC}=?$

Since we know that ABCD is a rectangle, we know that AC is parallel to BD.

Therefore, angles ACB and CBD are equal (30 degrees).

In a rectangle, we know that all angles are equal to 90 degrees, meaning angle ABD is equal to 90.

Now we can calculate angle ABC as follows:

$90-30=60$