A triangle and a parallelogram have the same base and the same area. If the sides of the triangle are 26 cm, 28 cm and 30 cm, and the parallelogram stands on the base 28 cm. Find the height of the parallelogram.

Let the width of the reservoir be x m. If 18 kl of water is removed from the reservoir, the water level goes down by 15 cm = 0.15 m.

Hence, the width of the reservoir is 6 m.