You may have come across many objects in daily life, which are round in shape, such as the wheels of a vehicle, bangles, dials of many clocks, coins of denominations of $50, key rings, buttons of shirts, etc. In a clock, you might have observed that the second’s hand goes around the dial of the watch rapidly and its tip moves in a round path. This path traced by the tip of the second’s hand is called a circle. In this book, you will study circles, other related terms, and some properties of a circle.