SAT Math Formulas Study Guide 2026/2027 | Complete Formula Sheet & Digital SAT Math Prep
Same Side Interior Angles (Parallel Lines) Ex. 3 & 5 add up to 180º
Area of a Triangle A=½(Base)(Height)
A=½bh
Triangle Inequality Theorem The sum of the 2 shortest sides of a triangle is always greater than the length of
the third side.
Equilateral Triangle A triangle in which all three sides are equal and all three interior angles are 60°.
Isosceles Triangle A triangle with two equal sides. Base angles (angles across from the congruent
sides) are also equal.
Proportionality in Triangles In every triangle, the longest side is opposite the largest angle and the smallest
side is opposite the smallest angle.
Pythagorean Theorem Used to find the missing side of a right triangle.
"c" is always the length of the hypotenuse.
a²+b²=c²
, SAT Math Formulas Study Guide 2026/2027 | Complete Formula Sheet & Digital SAT Math Prep
Similar Triangles Triangles that have the same angle measures but different side lengths. Solve
by setting up a proportion.
45-45-90 Special Triangle Always in the ratio 1:1:√2
Isosceles right triangle
30-60-90 Special Triangle Always in the ratio 1:√3:2
Pythagorean Triple Three integers that, as side lengths of a triangle, form a right triangle.
Ex. 3/4/5 or 5/12/13
Degree Measure of a Triangle The inside angles of a triangle always add up to 180°.
Area of a Circle A=πr²
Degree Measure of a Circle The central angles of a circle add up to 360°.
Circumference of a Circle C=2πr or C=πd
Same Side Interior Angles (Parallel Lines) Ex. 3 & 5 add up to 180º
Area of a Triangle A=½(Base)(Height)
A=½bh
Triangle Inequality Theorem The sum of the 2 shortest sides of a triangle is always greater than the length of
the third side.
Equilateral Triangle A triangle in which all three sides are equal and all three interior angles are 60°.
Isosceles Triangle A triangle with two equal sides. Base angles (angles across from the congruent
sides) are also equal.
Proportionality in Triangles In every triangle, the longest side is opposite the largest angle and the smallest
side is opposite the smallest angle.
Pythagorean Theorem Used to find the missing side of a right triangle.
"c" is always the length of the hypotenuse.
a²+b²=c²
, SAT Math Formulas Study Guide 2026/2027 | Complete Formula Sheet & Digital SAT Math Prep
Similar Triangles Triangles that have the same angle measures but different side lengths. Solve
by setting up a proportion.
45-45-90 Special Triangle Always in the ratio 1:1:√2
Isosceles right triangle
30-60-90 Special Triangle Always in the ratio 1:√3:2
Pythagorean Triple Three integers that, as side lengths of a triangle, form a right triangle.
Ex. 3/4/5 or 5/12/13
Degree Measure of a Triangle The inside angles of a triangle always add up to 180°.
Area of a Circle A=πr²
Degree Measure of a Circle The central angles of a circle add up to 360°.
Circumference of a Circle C=2πr or C=πd
