To find the area of a trapezoid, Dylan uses the formula [tex]$A = \frac{1}{2}(b_1 + b_2)h$[/tex]. The bases have lengths of [tex]3.6 \, \text{cm}[/tex] and [tex]12 \frac{1}{3} \, \text{cm}[/tex]. The height of the trapezoid is [tex]\sqrt{5} \, \text{cm}[/tex].

The area of the trapezoid is irrational because:

A. The values of the variables are all irrational numbers.
B. The entire answer is being multiplied by a fraction.
C. The height is irrational, and it is multiplied by the other rational dimensions.
D. The bases have an irrational sum that will be multiplied by the rational height.



Answer :

To find the area of the trapezoid, we can use the formula for the area of a trapezoid:
[tex]\[ A = \frac{1}{2} (b_1 + b_2) h \][/tex]

Given the values:
- [tex]\( b_1 = 3.6 \)[/tex] cm
- [tex]\( b_2 = 12 \frac{1}{3} \)[/tex] cm
- [tex]\( h = \sqrt{5} \)[/tex] cm

First, let's convert [tex]\( b_2 \)[/tex] from a mixed number to an improper fraction:
[tex]\[ b_2 = 12 \frac{1}{3} = 12 + \frac{1}{3} = 12 + 0.33333\ldots = 12.33333\ldots \][/tex]

The sum of the bases [tex]\( b_1 \)[/tex] and [tex]\( b_2 \)[/tex] is:
[tex]\[ b_1 + b_2 = 3.6 + 12.33333\ldots = 15.93333\ldots \][/tex]

Now, let's check the height [tex]\( \sqrt{5} \)[/tex]. The square root of 5 is an irrational number because it cannot be expressed as a fraction of two integers.

The values we need for the area calculation are:
- Sum of bases: [tex]\( b_1 + b_2 = 15.93333\ldots \)[/tex] cm (rational)
- Height: [tex]\( h = \sqrt{5} \)[/tex] cm (irrational)

According to the formula, the area [tex]\( A \)[/tex] is:
[tex]\[ A = \frac{1}{2} (b_1 + b_2) h \][/tex]

When an irrational number (the height, [tex]\( h = \sqrt{5} \)[/tex]) is multiplied by a rational number (the sum of the bases, [tex]\( b_1 + b_2 = 15.93333\ldots \)[/tex]), the result is generally irrational.

Thus, the area of the trapezoid is irrational because the height is irrational, and it is multiplied by the other rational dimensions.