若△ABC三边长分别为根号m²+16n²,根号9m²+4n²,根号4m²+4n²,(m＞0,n＞0,且m形的面积.

若△ABC三边长分别为根号m²+16n²,根号9m²+4n²,根号4m²+4n²,(m＞0,n＞0,且m形的面积.
若△ABC三边长分别为根号m²+16n²,根号9m²+4n²,根号4m²+4n²,(m＞0,n＞0,且m
形的面积.

若△ABC三边长分别为根号m²+16n²,根号9m²+4n²,根号4m²+4n²,(m＞0,n＞0,且m形的面积.
如图
S△ABC
=3m*4n-2n*2m/2-2n*3m/2-4n*m/2
=12mn-2mn-3mn-2mn
=5mn