Geometry skills final exam review

2026 geometry final review.

Midpoint

cuts a segment into 2 congruent segments

Segment bisector

passes thru the midpoint

Angle bisectors

lines or segments that divide an angle into two equal parts.

Vertical angles

Vertical angles are the angles opposite each other when two lines intersect, and they are congruent.

Supplementary angles

are two angles whose measures add up to 180 degrees.

Complementary angles

are two angles whose measures add up to 90 degrees.

Triangle side theorem

• Largest angle is the opposite of the largest side

• Smallest angle is opposite smallest side

Exterior angle sum theorem

Sum of 2 remote interior angles is equal to the exterior angle

Alternate interior angles

Makes a Z, congruent

Corresponding angles

Makes a F, congruent

Same Side interior Angles

Makes a C, supplementary

Slope of parallel lines

Congruent slopes

Slope of perpendicular lines

slopes are negative reciprocals

Slope-intercept form

y=mx+b

point-slope formula

y-y1=m(x-x1)

Horizontal lines

zero slope

Vertical lines

No/undefined slope

Interior angle sum

(sides-2)180

Exterior angle sum

360

1 interior angle sum

(sides-2)180/sides

when you get the “find 1 interior 1 exterior” DO EXTERIOR FIRST

1 exterior angle

360/sides

parallelogram properties

• opposite sides parallel

• opposite sides congruent

• opposite angles congruent

• diagonals bisect each other

• consecutive angles are supplementary

Rectangle

• diagonals congruent

• 4 congruent (right) angles

Rhombus

• 4 congruent sides

• perpendicular diagonals

• diagonals bisect angles

Square

all properties

Trapezoids median

base1+base2/2

AA similarity theorem

Compare little triangle to big triangle

Altitude rule

Central angle…

Equals arc

Inscribed angle

½ of the arc

Slope formula

m= y2-y1/x2-x1

Midpoint formula

m=(x1 + x2)/2, (y1 + y2)/2

Distance formula

d = ( x 2 − x 1 )² + ( y 2 − y 1 )²

Arc length

Central angle/360 × 2π(radius)

Sector (slice of circle) Area

Central angle/360 × 2π(radius)²