Important Geometry Formulas for the ACT

Important Geometry Formulas for the ACT

DLB

On a sheet of paper, you should copy the following and then write the formula beside each one.

• Area of a Circle

• Circumference of a Circle

• Area of a Square

• Perimeter of a Square

• Area of a Rectangle

• Perimeter of a Rectangle

For all coordinate geometry formulas, use (x₁,y₁) and (x₂,y₂) for the points.

• Midpoint

• Distance

• Slope

• Point-Slope Form of a Line

• Slope-Intercept Form of a Line

• Equation of a Circle

When you finish, you should have 18 formulas!

• Arc Length

• Area of a Sector

• Pythagorean Theorem

• Area of a Parallelogram

• Area of a Triangle

• Area of a Trapezoid

Multiple Choice

What is the midpoint formula?

• $\frac{y_2-y_1}{x_2-x_1}$

•  $\left(\frac{x_1+x_2}{2},\ \frac{y_1+y_2}{2}\right)$  
  

•  $\left(\frac{x_1-x_2}{2},\ \frac{y_1-y_2}{2}\right)$  

•  $\sqrt{\left(x_2-x_1\right)^2+\left(y_2-y_1\right)^2}$  

Multiple Choice

What is the formula for area of a triangle?

•  $bh$  

•  $\frac{1}{2}bh$  

•  $lw$  

•  $\pi r^2$  

Multiple Choice

What is the formula for area of a square?

•  $lwh$  

•  $s^2$  

•  $lw$  

•  $4s$  
  

Multiple Choice

What is the formula for perimeter of a square?

•  $lwh$  

•  $s^2$  

•  $lw$  

•  $4s$  
  

Multiple Choice

What is the formula for perimeter of a rectangle?

•  $bh$  

•  $4bh$  

•  $2l+2w$  

•  $lw$  
  

Multiple Choice

What is the formula for Pythagorean Theorem?

• $2\pi r$

• $c^2=a^2+b^2$

• PEMDAS

• SOH CAH TOA

Multiple Choice

What is the distance formula?

• $\frac{y_2-y_1}{x_2-x_1}$

• $\sqrt{\left(x_2-x_1\right)^2+\left(y_2-y_1\right)^2}$

• $\sqrt{\left(x_2+x_1\right)^2-\left(y_2+y_1\right)^2}$

• $d^2=a^2+b^2$

Multiple Choice

What is the formula for slope?

• $y=mx+b$

• $\frac{y_2-y_1}{x_2-x_1}$

• $\frac{x_2-x_1}{y_2-y_1}$

• $y-y_1=m\left(x-x_1\right)$

Multiple Choice

What is the formula for the area of a rectangle?

• $lw$

• $\frac{1}{2}bh$

• $\pi r^2$

• $2h\left(b_1+b_2\right)$

Multiple Choice

What is the point-slope form of the equation of a line?

• $y=mx+b$

• $y-y_1=m\left(x-x_1\right)$

• $r^2=\left(x-h\right)^2+\left(y-k\right)^2$

• $a^2+b^2=c^2$

Multiple Choice

What is the slope-intercept form of the equation of a line?

• $y=mx+b$

• $y-y_1=m\left(x-x_1\right)$

• $r^2=\left(x-h\right)^2+\left(y-k\right)^2$

• $a^2+b^2=c^2$

Multiple Choice

What is the equation of a circle?

• $A=\pi r^2$
  

• $y-y_1=m\left(x-x_1\right)$

• $r^2=\left(x-h\right)^2+\left(y-k\right)^2$

• $a^2+b^2=c^2$

Multiple Choice

What is the formula for area of a parallelogram?

•  $bh$  

•  $\frac{1}{2}bh$  

•  $lw$  

•  $\pi r^2$  

Multiple Choice

What is the formula for arc length?

• $\pi r^2$

• $\frac{\theta}{360}\pi r^2$

• $\frac{\theta}{360}\pi d$

• $4\pi r^3$

Multiple Choice

What is the formula for area of a sector of a circle?

• $\pi r^2$

• $\frac{\theta}{360}\pi r^2$

• $\frac{\theta}{360}\pi d$

• $4\pi r^3$

Multiple Choice

What is the formula for area of a trapezoid?

• $\frac{1}{2}h\left(b_1+b_2\right)$

• $bh$

• $\frac{1}{2}bh$

• $2h\left(b_1+b_2\right)$

Multiple Choice

What is the formula for circumference of a circle?

•  $2\pi d$  

• $2\pi r$

• $\pi r^2$

• $\frac{4}{3}\pi r^3$

Multiple Choice

What is the formula for area of a circle?

• $\pi d$

• $2\pi r$

• $\pi r^2$

• $\frac{4}{3}\pi r^3$