Question

classify the four angles of the quadrilateral.

Explanation:

Step1: Recall angle definitions

• A right angle is \(90^{\circ}\).
• An acute angle is between \(0^{\circ}\) and \(90^{\circ}\).
• An obtuse angle is between \(90^{\circ}\) and \(180^{\circ}\).

Step2: Classify \(\angle A\)

\(\angle A = 90^{\circ}\), so it is a right angle.

Step3: Classify \(\angle B\)

\(\angle B=80^{\circ}\), and \(0^{\circ}<80^{\circ}<90^{\circ}\), so it is an acute angle.

Step4: Classify \(\angle C\)

\(\angle C = 140^{\circ}\), and \(90^{\circ}<140^{\circ}<180^{\circ}\), so it is an obtuse angle.

Step5: Classify \(\angle D\)

\(\angle D=70^{\circ}\), and \(0^{\circ}<70^{\circ}<90^{\circ}\), so it is an acute angle.

Answer:

• \(\angle A\): Right
• \(\angle B\): Acute
• \(\angle C\): Obtuse
• \(\angle D\): Acute