# Angle In A Circle 1

- Author:
- Yopi Tobriyanto

## Inscribe Angle and Central Angle

**ACB**is called

__central angle__or

__angle at the centre__subtended

**arc AB**.

**ADB**is called

__inscribed angle__or

__angle at the circumference__subtended

**arc AB**. Do the following instruction and try to answer the question!

## 1. Inscribed Angle

Move point D along **arc AB**, then pay attention to **ADB**.
What do you think about **ADB** when you move point D?
(*Note : Move the points A or/and B to change the angle*)

## 2. Central Angle

Move points A and B, then pay attention to **ACB** and the measure of **arc AB**.
What do you think about the measure of **ACB** and **arc AB **when you move points A and B?

## 3. Relation Of Central Angle and Inscribed Angel

Move points A and B, then pay attention to **ACB** and **ADB**.
What do you think about the relation of **ACB** and **ADB **measurement values?
(*Hint : Try to add, subtract, times or divide both angles for several different measurement value, and write your discovery result as the answer.*)

## 4. Conclution

Write your conclusions based your discovery result, and discuss with your workgroup to complete the group report!