Let the base of the parallelogram be x m.
Then, the altitude of the parallelogram will be 2x m.
It is given that the area of the parallelogram is 338 m2.
Area of a parallelogram = Base × Altitude
∴ 338 m2 = x × 2x
338 m2 = 2x2
⇒ x2 = m2 = 169 m2
⇒ x2 = 169 m2
⇒ x = 13 m
∴ Base = x m = 13 m
Altitude = 2x m = (2 × 13)m = 26 m