Geometry

Vertex to midpoint of the opposite side

Median

Vertex to opposite side at right angle

Altitude

Cuts an angle into two equal angles

Angle bisector

Hits a side at a right angle and cuts it in half

Perpendicular bisector

Perpendicular bisectors intersect

Circumcenter

Angle bisectors intersect

Incenter

Medians intersect

Centroid

Altitudes intersect

Orthocenter

Midpoint

(X1+X2/2, Y1+Y2/2)

Slope formula

(Y2-Y1) / (X2-X1)

Slope Intercept Form

y=mx+b

Standard form

Ax+By, A can’t be negative, and no fractions

Point slope formula

y-y1=m(x-x1)

90 rotation

(x,y) to (-y,x)

180 rotation

(x,y) to (-x,-y)

270 rotation

(x,y) to (y,-x)

Methods to prove triangles are congruent

SAS, AAS, HL, ASA, SSS

Arc length formula

L= m/360 × 2 x pie x r

Area of a sector formula

A= m/360 x pie x r squared

Equation of a circle

(x-h) squared + (y-k) squared = radius squared