# Quadrilateral Inscribed in a Circle – Cyclic Quadrilateral

- Author:
- Jose Mari M. Calamlam

- Topic:
- Circle

## Objectives

The objectives of this activity is to discover some properties of cyclic quadrilaterals.

Instructions:
1. Given points A, B, C and D on circle O.
2. Draw segments AB, BC, CD, and DA to form quadrilateral ABCD.
3. Find the measure of angles A, B, C, and D.
4. Answer follow-up questions

Identify the pairs of opposite angles. *(Note: opposite angles are non-consecutive angle)*

Add the measures of opposite angles. What do you observe with their sums?

Try moving points A, B, C, and D. Does your observations changed?

Based on your observations, what do you conclude to the opposite angles of cyclic quadrilaterals?