What is the area of trapezoid abcd? enter your answer as a decimal or whole number in the box. do not round at any steps

The side length AB is √(3²+4²) = 5.

Let's split up the shape in a square and a triangle.

If you introduce point E at (5,1) you see a square ABED with area 5*5=25.
What remains is a triangle with straight sides 5 and √((11-5)² + (1--7)²) = 10. So the triangle's area is 5*10/2 = 25.

This means the total area is 25+25=50.