Find the area of a right-angled triangle, the legs of which: a) AB = 30 mm, BC = 4 cm. Express the area of this triangle in square millimeters; b) KN = 5dm, NM = 600mm. Express the area of this triangle in square centimeters; c) FL = 70m, LD = 60dm. Express the area of this triangle in square decimeters.

Area of a right triangle: S = a * b / 2

1. BC = 40mm
S = 30 * 40/2 = 600 mm2
Answer: 600mm2

2. KN = 50 cm, NM = 60 cm
S = 60 * 50/2 = 1500 cm2
Answer: 1500cm2

3. FL = 70dm
S = 70 * 60/2 = 2100 dm2
Answer: 2100dm2