The sides of the parallelogram are 7: 3, one of them is 12cm smaller than the other.

The sides of the parallelogram are 7: 3, one of them is 12cm smaller than the other. Find the area of a parallelogram if its angle is 120 degrees.

One side of a parallelogram is 7 parts, the other side of a parallelogram is 3 parts. Let’s find the difference of the sides in parts.

7 – 3 = 4 parts.

The difference in 4 parts is 12 centimeters. Let’s find the length of one part.

12 cm ÷ 4 = 3 cm.

Find the length of one side.

7 * 3 cm = 21 cm.

Find the length of the other side.

3 * 3 cm = 9 cm.

Find the area of the parallelogram. Multiply one side by the other and by the sine of the angle between them.

S = 21 cm * 9 cm * sin120 ° = 189 cm² * 0.866 = 163.67 cm².

Answer: the area of the parallelogram is 163.67 cm².



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