SAT Math

How to prove two triangles are similar?

• All three corresponding sides are proportional

• Are three angles on each triangle are congruent to each other

How to know if a triangle is isosceles

• Two congruent sides

• 2 angles opposite the congruent sides are equal

MUST KNOW

If two angles add up to 90 degrees, the sine of one of the angles is equal to the cosine of the other angle (Vice versa)

Degrees to radians

Degrees times ℼ/180

Radians to degrees

Radians times 180/ℼ

Sum of interior angles of a polygon

180(n-2) (n = number of sides)

Sum of exterior angles of a polygon

360 degrees

Distance formula

Surface Area of Cube

6s²

Surface area of a rectangular prism

2lw + 2lh + 2wh

Arc length for a circle formula

Number of degrees/360 (2ℼ r)

Area of a sector formula

Number of degrees/360 times (ℼ r)²

Inscribed angle

½ measure of the arc

When a square is inscribed in a circle

the square's diagonal is the circle's diameter

Diagnol of a square

side length times square root of 2

exponential growth/decay formula

Amount = Initial (1 + or - r)^t (r = rate as a decimal) (t = time in yrs unless otherwise stated)

Cylinder Surface Area

SA = 2ℼr² + 2ℼrh

Sphere surface area

SA = 4ℼ r²

Cone surface area

SA = ℼ r² + ℼrl

Vertex of Parabola

x = -b/2a (plug x into original equation for y value)

Vertex Form of Parabola

a(x-h)² + k = y

Standard Form of Parabola

y = ax² + bx + c