Lines, Angles, and Curves

the central point or line around which an object turns

The Earth spins on its axis once every twenty-four hours.

to go across or to the other side of something

Every morning, he crosses the bridge on his way to work.

(of a straight line) joining opposite corners of a flat shape at an angle

The diagonal line on the graph represented the trend of increasing sales over time.

(geometry) a shape that consists of a line alternating its direction to left and right

a straight line that is terminated by a secondary line at each end, resembling the letter H

a flat-bodied marine cartilaginous fish with eyes on the upper surface, swimming primarily using large, wing-like pectoral fins

The diver spotted a manta ray gliding over the reef.

a portion of a straight line that is defined by two distinct endpoints

having an equal distance from each other at every point

The two lines on the graph are parallel, indicating no change in their relationship.

(of lines or planes) intersecting each other at a 90 degree angle

In technical drawings, architects ensure walls are precisely perpendicular to allow for square structures.

a straight line that touches a curve or surface at exactly one point, known as the point of tangency

In geometry class, we learned how to draw a tangent to a circle, ensuring it only touched the circle at a single point.

a line that crosses a curve at least at two distinct points

By drawing a secant, the mathematician was able to study the curve’s behavior at multiple points.

a pair of adjacent angles formed by two intersecting lines, which add up to 180 degrees

an angle that measures between 0 and 90 degrees, which is less than a right angle (90 degrees)

an angle that measures more than 90 degrees but less than 180 degrees

In a triangle, an obtuse angle is one that is greater than 90 degrees but less than 180 degrees.

an angle measuring exactly 90 degrees

To construct a square, each corner must form a perfect right angle.

an angle that measures exactly 180 degrees, which is the same as a straight line

an angle that measures either less or more that 90 degrees

In a parallelogram, opposite angles are oblique angles since they are not right angles.

an angle that measures greater than 180 degrees but less than 360 degrees

a complete revolution or turn around a fixed point or axis, covering a 360-degree angle

an angle measured counterclockwise from the initial side of a reference angle in standard position, usually expressed in degrees or radians

an angle measured clockwise from the initial side of a reference angle in standard position, usually expressed in degrees or radians

two angles that share a common vertex and a common side, but do not overlap, and are not in a straight line

the measure of the tilt between two lines or surfaces in two-dimensional space, typically given in degrees or radians

The clock's hands form a plane angle at noon.

(geometry) a part of a circle, which is curved

In a circle, a minor arc is shorter than a major arc.

a shape, line or surface that is hollow and is rounded inward

(geometry) a shape formed when a circular cone is intersected by a plane

a curved shape with narrow points at the ends that appears wider in the middle, like the shape of the moon in its first and last quarters

The moon hung low in the sky, its slender crescent casting a gentle light.

a strand of hair that is spiraled or wavy

She brushed a loose curl from her face.

to move or extend in a continuous and widening circular pattern

The smoke has spiraled upward from the chimney into the night sky.

(geometry) a closed plane curve that has two focal points

(geometry) a symmetrical open curve that is similar to the path of an object thrown into the air passes till it falls back to earth

The path of a thrown ball forms a parabola.

a geometric curve formed by the intersection of a plane with two cones, resulting in two symmetrical branches

The hyperbola is a conic section formed by intersecting a plane with two cones on opposite sides of the plane.

a continuous curve that does not intersect itself, and can be traced without lifting the pen or pencil from the paper

a curve that intersects itself, or has overlapping segments, requiring the pen or pencil to be lifted from the paper while tracing it

a curve that does not intersect itself and has distinct endpoints, meaning it does not form a closed shape or loop

a curve that begins and ends at the same point, forming a closed loop