Detailed Instructions: In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Q: Problem: if the sides of a triangle are 28 cm , 24 cm and 15 cm , what is its area ? 
Options: a ) 180 cm 2 , b ) 112 cm 2 , c ) 776 cm 2 , d ) 666 cm 2 , e ) 886 cm 2
A:
a