personal geometry sat flashcards

equilateral triangle height formula

√3/2

area of equilateral triangle

√(3)/4a² = h²/√(3)

perimeter of equilateral triangle

3a

45 45 90 triangles

x, x, x√(2). and x/√(2), x/√(2), x

30 60 90 triangles

x, x√3, 2x OR x/√3, x, 2x/√3 OR x/2, x√3/2, x

similar triangles

AAA, SSS, SAS, AA

congruency theorems

SAS, SSS, ASA, AAS, HL

sin A = cos (90-A)

A+(90-A)=90

sin A = cos B

A+B=90

area of sector

(θ° / 360°) × πr²

Standard Equation of a Circle

Ax^2 + Ay^2 + Bx + Cy + D = 0

The measure of a minor arc is

the measure of the central angle containing the arc.

measure of the major arc is

360-θ

When central angle is in degrees, the length of an arc

$$\frac{\theta^\circ}{360^\circ} \times 2\pi r$$

if two arcs of a circle are congruent then

corresponding chords are equal and converse is also true

corresponding angles at the centre are equal and converse is true

corresponding lengths of arcs are equal and converse is also true

POQ

2PRQ

reflex POQ

2PMQ

diameter of a circle connected to any point on the circumference of the circle

forms a right angle triangle at the circumference of a circle