Question

find the area of the triangle.
18 mm
21 mm
the area is \square square millimeters.

Explanation:

Step1: Recall triangle area formula

The area of a triangle is given by $\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}$

Step2: Substitute given values

Here, base $=21$ mm, height $=18$ mm. Substitute into the formula:
$\text{Area} = \frac{1}{2} \times 21 \times 18$

Step3: Calculate the result

First compute $21 \times 18 = 378$, then multiply by $\frac{1}{2}$:
$\text{Area} = \frac{378}{2} = 189$

Answer:

189