To find the area of the parallelogram, we first need to find the length of the other diagonal, as both diagonals of a parallelogram bisect each other and create four congruent right triangles.
Let's label the sides of the parallelogram as follows:
AB = 15 cm (one side)
BC = 20 cm (adjacent side)
AC = diagonal (25 cm)
Using the Pythagorean theorem, we can find the length of the other diagonal (BD):
BD^2 = AB^2 + AD^2
Since the diagonals bisect each other, AD is half the length of the diagonal AC. Thus, AD = AC/2.
Substituting the values, we get:
BD^2 = 15^2 + (25/2)^2
BD^2 = 225 + 625/4
BD^2 = 900/4 + 625/4
BD^2 = 1525/4
BD = √(1525/4) ≈ 19.56 cm
Now that we have the lengths of both diagonals (AC = 25 cm and BD ≈ 19.56 cm), we can calculate the area of the parallelogram using the formula:
Area = (1/2) * AC * BD
Substituting the values:
Area = (1/2) * 25 cm * 19.56 cm
Area ≈ 244.5 cm^2
Therefore, the area of the parallelogram is approximately 244.5 square centimeters.