5th grade geometry terms

quadrilateral

A polygon with 4 sides.

triangle

A polygon with 3 sides.

acute angle

An angle less than 90 degrees.

obtuse angle

An angle with greater than 90 degrees.

perpendicular

Intersecting at right angles.

polygon

A closed figure made with three or more line segments.

ray

A half-line extending from a point.

right angle

An angle that is exactly 90 degrees.

square

A quadrilateral with 4 equal sides and 4 90 degree angles.

isosceles triangle

A triangle with at least 2 equal sides.

scalene triangle

A triangle with 3 unequal sides.

parallel lines

Lines that do not intersect.

parallelogram

A quadrilateral with opposite parallel lines.

rhombus

A parallelogram that opposite congruent angles and sides. Ex: a square that appears to lean.

trapezoid

A quadrilateral with only two parellel sides.

obtuse triangle

a triangle with one obtuse angle

equilateral triangle

a triangle with three equal sides

intersecting lines

Lines that cross at exactly one point

line

a straight path that extends infinitely in one direction

rectangle

a parallelogram with four right angles

angle

two rays or line segments with a common endpoint