# What is the convex and concave?

**Convex and concave**are two words that describe a line or shape, often in mathematics, science, or in relation to eyeglasses and mirrors. While

**convex**means to bend or protrude outwards,

**concave**is the opposite and means to bend inwards.

Regarding this, what is concave and convex surface?

**Concave** is an adjective that describes a **surface** that curves inward, or is thinner in the middle than on the edges. In ordinary usage, **concave and convex** are typically used when referring to glass **surfaces**, like the lenses of optical viewing equipment. The side mirror of a car has a **concave surface**.

Additionally, what is a convex shape? A **convex** polygon is defined as a polygon with all its interior **angles** less than 180°. This means that all the vertices of the polygon will point outwards, away from the interior of the **shape**. Note that a triangle (3-gon) is always **convex**. A **convex** polygon is the opposite of a concave polygon.

Also Know, what is concave convex rule?

The “**concave** on **convex**” **rule** Instead of moving the ball, move and roll your palm around the stationary ball. As your palm rolls around the ball, it also glides in the same direction. So, when a **concave** joint surface is moving on a **convex** joint surface, roll and glide occur in the SAME direction.

What shape is concave?

Curved inwards. Example: A polygon (which has straight sides) is **concave** when there are "dents" or indentations in it (where the internal angle is greater than 180°)