Answer:
The area of triangle is 25 square units.
Step-by-step explanation:
Given information: Vertices of the triangle are (2,1), (10,-1), and (-1,8).
Formula for area of a triangle:

The given vertices are (2,1), (10,-1), and (-1,8).
Using the above formula the area of triangle is



On further simplification we get



Therefore the area of triangle is 25 square units.