Angles
An angle less than 90 degrees.
Acute Angle
A triangle with three equal sides.
Equilateral Triangle
A quadrilateral with exactly one pair of parallel sides.
Trapezoid
The distance from the center to the edge of a circle.
Radius
It states that a² + b² = c² in a right triangle.
Pythagorean Theorem
An angle equal to 90 degrees.
Right Angle
A triangle with two equal sides.
Isosceles Triangle
A quadrilateral with all sides equal but angles not necessarily 90 degrees.
Rhombus
The distance across a circle passing through the center.
Diameter
The formula for the area of a triangle.
½bh
An angle greater than 90 degrees but less than 180 degrees.
Obtuse Angle
A triangle with one 90-degree angle.
Right Triangle
A quadrilateral with opposite sides equal and four right angles.
Rectangle
The formula for the area of a circle.
πr²
The formula for the area of a rectangle.
length × width
Two angles that add up to 90 degrees.
Complementary Angles
The sum of the interior angles of a triangle.
180 degrees
A quadrilateral with two pairs of adjacent equal sides.
Kite
The formula for the circumference of a circle.
2πr
The midpoint formula in coordinate geometry.
((x1 + x2)/2, (y1 + y2)/2)
Two angles that add up to 180 degrees.
Supplementary Angles
The longest side of a right triangle.
Hypotenuse
The sum of the interior angles of any quadrilateral.
360 degrees
The constant approximately equal to 3.14.
π/Pi
The formula for the perimeter of a rectangle.
2(l + w)