Question

area of triangle =?

Explanation:

Step1: Identify base and height

The figure ABCD is a square, so AB = BC = 6 cm. For $\triangle ACO$, we can use AB as the base, and BC as the height (since the distance from point C to line AO is equal to the side length of the square, because the circle is tangent to AB, so the distance from O to AB equals the radius, and the vertical distance from C to AB is 6 cm, making the height of $\triangle ACO$ equal to the side length of the square).

Step2: Apply triangle area formula

The area of a triangle is $\frac{1}{2} \times \text{base} \times \text{height}$. Substitute base = 6 cm, height = 6 cm.
$\text{Area} = \frac{1}{2} \times 6 \times 6$

Step3: Calculate the result

$\frac{1}{2} \times 6 \times 6 = 18$

Answer:

18 $\text{cm}^2$