Answer
See below
Work Step by Step
Given: $A=(x_A,y_A)\\B=(x_B,y_B)\\C=(x_C,y_C)$
are the verticles of the triangle.
Since we have $(0,0);(14,3);(6,25)$, then $x_A=0,y_A=0\\x_B=14,y_B=3\\x_C=6,y_C=25$
Formula of the area of the triangle is given by:
$\frac{1}{2}|x_A(y_B-y_C)+x_B(y_C-y_A)+x_C(y_A-y_B)\\
=\frac{1}{2}|0(3-25)+14(25-0)+6(0-3)\\
=\frac{1}{2}|350-18|\\
=\frac{1}{2}|332|\\
=166$