Exercise 7 Page p36

To calculate the probability of choosing a triangle, we use the Probability Formula.

P = \frac{Number of favorable outcomes}{Number of possible outcomes}

In our exercise the number of possible outcomes is

6,

as we have six polygons. Among them there are three triangles, so the number of favorable outcomes is

3 .

Now we can calculate

P (triangle) .

P = \frac{Number of favorable outcomes}{Number of possible outcomes}

Substitute values

P (triangle) = \frac{3}{6}

$\frac{a}{b} = \frac{a / 3}{b / 3}$

P (triangle) = \frac{1}{2}

The probability of picking a triangle is

\frac{1}{2} .