# Vertical

## Etymology

Middle French or Late Latin; Middle French, from Late Latin verticalis, from Latin vertic-, vertex

- Date: 1559

## Definitions

- 1 a : situated at the highest point : directly overhead or in the zenith

- b of an aerial photograph : taken with the camera pointing straight down or nearly so

- 2 a : perpendicular to the plane of the horizon or to a primary axis : upright

- b (1) : located at right angles to the plane of a supporting surface (2) : lying in the direction of an axis : lengthwise

- 3 a : relating to, involving, or integrating economic activity from basic production to point of sale <a vertical monopoly>

- b : of, relating to, or comprising persons of different status <the vertical arrangement of society>

## Description

In geometry, a pair of angles is said to be **vertical** (also opposite and vertically opposite, which is abbreviated as vert. opp. ∠s) if the angles are formed from two intersecting lines and the angles are not adjacent. They all share a vertex. Such angles are equal in measure and can be described as congruent.

## Vertical angle theorem

When two straight lines intersect at a point, four angles are formed . The nonadjacent angles are called vertical or opposite or vertically opposite angles. Also, each pair of adjacent angles form a straight line and are supplementary. Since any pair of vertical angles are supplementary to either of the adjacent angles, the vertical angles are equal in measure.[1]