Tools of Geometry

English	Spanish
acute angle	an angle with a measure greater than 0 degrees and less than 90 degrees
angle	two rays with a common endpoint
angle bisector	A ray that divides an angle into two congruent angles.
area	the number of square units needed to cover a flat surface
circumference	distance around a circle
collinear points	Points that lie on the same line.
complementary angles	Two angles whose measures have the sum of 90 degrees
congruent angles	Angles that have the same measure.
congruent segments	Segments that have the same length
coordinate	The number that corresponds to a point
coplanar	figures in the same plane
line	a series of points that extends in two opposite directions without end
midpoint	a point that divides a segment into two congruent segments
obtuse angle	An angle that measures more than 90 degrees but less than 180 degrees
opposite rays	two collinear rays with the same endpoint
parallel lines	lines in the same plane that never intersect
parallel planes	planes that do not intersect.
perimeter	The sum of the lengths of the sides of a polygon.
perpendicular bisector	a segment, ray, line, or plane that is perpendicular to a segment at its midpoint
perpendicular lines	Two lines that intersect to form right angles
plane	A flat surface that goes on forever in all directions
ray	part of a line with one endpoint
right angle	an angle that measures 90 degrees
segment	part of a line with two endpoints
skew lines	lines that do not lie in the same plane
straight angle	an angle whose measure is 180 degrees
supplementary angles	two angles that add up to 180 degrees
vertical angles	two angles whose sides form two pairs of opposite rays
Midpoint Formula	M = [ ( x₂ + x₁) / 2, (y₂ + y₁) / 2 ] To get your x-coordinate: Add the x's and divide by 2 To get your y-coordinate: Add the y's and divide by 2
Distance formula	d = √[( x₂ - x₁)² + (y₂ - y₁)²] It does not matter which point is labeled 1 and which is labeled 2
Perimeter of a Rectangle	P = 2L+2W where L = length and W = width
Perimeter of a Square	P = 4s where s = length of side
Circumference of a Circle	C=2πr or C=πd where r = radius and d = diameter and π = pi (approx. 3.14)
Area of a Square	A = s² where s = length of side
Area of a Rectangle	A = L x W where L=length and W = width
Area of Circle	A=πr² where r = radius and π = pi (approx. 3.14)