Fisrt is solve the distance of the segments using distance formula
Distance =sqroot[(x2−x1)^2+(y2−y1)^2]
So ditance of RS = 5
ST = 8.49
TR =6.08
The using herons formula
Area = sqrt ( s ( s-a) ( s-b) ( s-c) )
Where s s = 1/2 ( a + b + c )
And a, b , c are length of the sides
S = 9.785
Area = 14.99