Question

area of triangle =?

Explanation:

Step1: Identify base of triangle

Base $AB = 6\ \text{cm}$

Step2: Note height of triangle

Height = $AB = 6\ \text{cm}$ (since ABCD is a square)

Step3: Calculate triangle area

Use formula $\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}$
$\text{Area} = \frac{1}{2} \times 6 \times 6 = 18\ \text{cm}^2$

Answer:

$18\ \text{cm}^2$