Find the area of a parallelogram, the sides of which are 9 cm and 12 cm, and the angle between them is 60 degrees.

To calculate the area of a parallelogram, apply the formula:

S = a * b * sin a.

The area of a parallelogram is equal to the product of its sides by the sine of the angle between them.

From the condition, we know the lengths of the sides – 9 cm and 12 cm, and the angle between them is also known to be 60 °.

We just have to substitute the values in the formula and make calculations.

S = 9 * 12 * sin 60 °.

Let’s find first of all the sine of an angle of 60 °.

sin 60 ° = √3 / 2.

We calculate:

S = 9 * 12 * √3 / 2 = 54√3 cm ^ 2.

We write down the answer.

Answer: S = 54√3 cm ^ 2.