Question

The angle between two radii OA and OB is a straight angle, then AB is called____.

• A. diameter
• B. chord
• C. radius
• D. circumference

Answer 1

The correct option is A

diameter

In the above figure, OA and OB are two radii of the circle with center O. The angle between OA and OB is less than 180${}^{\circ }$. Rotate OB anti-clockwise, such that OA and OB will be at 180${}^{\circ }$. Then we will get a diagram as shown.

Clearly, AB is a chord passing through the center which makes it the longest chord i.e, the diameter.