Question

Given below is the area of three triangles. Fill in the blanks with their base or height as applicable.

Answer 1

Hint: Here, we will proceed by using the formula of the area of the triangle.
We know that the area of triangle = $\frac{1}{2} \times base \times height$
From the given data, we have
In first row, measurements of base and area of a triangle are given as
$base = 15cm$ and $area = 87c{m^2}$
Substituting these values in the formula of area of triangle, then
$\therefore 87 = \frac{1}{2} \times 15 \times height$
$ \Rightarrow height = \frac{{87 \times 2}}{{15}} = 11.6cm$

In second row, measurement of height and area of a triangle are given as
$height = 31.4cm$ and $area = 1256m{m^2}$
Substituting these values in the formula of area of triangle, then
$\therefore 1256 = \frac{1}{2} \times base \times 31.4$
$ \Rightarrow base = \frac{{1256 \times 2}}{{31.4}} = 80cm$

In third row, measurements of base and area of a triangle are given as
$base = 22cm$ and $area = 170.5c{m^2}$
Substituting these values in the formula of area of triangle, then
 $\therefore 170.5 = \frac{1}{2} \times 22 \times height$
 $ \Rightarrow height = \frac{{170.5 \times 2}}{{22}} = 15.5cm$
We got all the missing values of the given data.
Thus, the missing values in the given table are:

Base	Height	Area of triangle
15cm	11.6cm	87$c{m^2}$
80mm	31.4mm	1256$m{m^2}$
22cm	15.5cm	170.5$c{m^2}$

Note: To find the area enclosed by a triangle, we multiply the base by the height, and then divide by 2. The division by 2 comes from the fact that a parallelogram can be divided into 2 triangles. That means, the area of each triangle is equal to one-half the area of the parallelogram. While calculating the area, we need to make sure that the base and height are in the same units (like cm or mm). If they are not in the same units, we need to convert them into the same units.