Calculate the area of a triangle, if the sides are 30 cm, 21 cm and 10 cm, what is its area? Options:
A) 145 cm 2
B) 105 cm 2
C) 125 cm 2
D) 115 cm 2
E) 135 cm 2

Rationale: "the triangle with sides 30 cm , 21 cm and 10 cm is right angled , where the hypotenuse is 30 cm . area of the triangle = 1 / 2 * 21 * 10 = 105 cm 2 answer : b"
Answer: B