## List of Math Formulas for 9th-grade Students

Here are some important math formulas for 9th-grade students:

### 1. Pythagorean Theorem

In a right triangle, the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides.

a^{2} + b^{2} = c^{2}

### 2. Distance Formula

The distance between two points (x1, y1) and (x2, y2) in a coordinate plane is given by the formula:

d = sqrt((x2 – x1)^{2} + (y2 – y1)^{2})

### 3. Slope Formula

The slope of a line passing through two points (x1, y1) and (x2, y2) is given by the formula:

m = (y2 – y1)/(x2 – x1)

### 4. Quadratic Formula

The roots of a quadratic equation ax^{2} + bx + c = 0 can be found using the quadratic formula:

x = (-b ± sqrt(b^{2} – 4ac))/2a

### 5. Law of Sines

In a triangle, the ratio of the length of a side to the sine of the angle opposite that side is constant for all sides and angles.

a/sin A = b/sin B = c/sin C

### 6. Law of Cosines

In a triangle, the square of the length of a side is equal to the sum of the squares of the other two sides minus twice the product of those sides and the cosine of the angle between them.

a^{2} = b^{2} + c^{2} – 2bc cos A

### 7. Exponential Growth/Decay Formula

The amount A of a quantity that grows or decays exponentially with time t can be modeled using the formula:

A = A0 e^{(kt)}, where A0 is the initial amount, k is the growth/decay rate, and e is the base of natural logarithms.

These formulas cover a range of topics such as geometry, algebra, trigonometry, and exponential functions, and are essential for 9th-grade students to master as they continue to study more advanced math concepts.