Q9. - Algebra 1

Question

One of the polygons below is chosen at random. Find each probability.

P (not a quadrilateral)

Step-by-Step Solution

Answer

The probability of getting a figure that is not a quadrilateral is $\frac{2}{3}$.

Step 1. Count the numbers of quadrilaterals.

Note that a quadrilateral is a polygon with four sides.

Among the given figures, there are 2 figures that have four sides hence, are quadrilaterals and the rest 4 figures are not quadrilaterals.

Step 2. Apply the basic formula for probability.

The probability of an event is given by the following formula:

$\mathrm{Probability} \mathrm{of} \mathrm{an} \mathrm{event}=\frac{\mathrm{number} \mathrm{of} \mathrm{favorite} \mathrm{outcome}}{\mathrm{total} \mathrm{outcome}}$

Step 3. Write the given information.

The total number of figures is 6.

 

The number of favorite outcomes is 4 since there are four figures that are not quadrilaterals among the given figures.

Step 4. DESCRIPTION OF STEP.

Substitute the value of the number of favorite outcomes and total outcomes in the formula for probability.

$$\begin{gathered} \mathrm{P}\left(\mathrm{Not} \mathrm{a} \mathrm{quadrilateral}\right)=\frac{\mathrm{number} \mathrm{of} \mathrm{favorite} \mathrm{outcome}}{\mathrm{total} \mathrm{outcome}} \\ =\frac{4}{6} \\ =\frac{2}{3} \end{gathered}$$

Hence, the probability of getting a figure that is not a quadrilateral is $\frac{2}{3}$.