Answer:
The area is 5 units²
Explanation:
∵ The area of the square of side length 3 which contains
the quadrilateral ABCD = 3 × 3 = 9 units²
∵ The area of the 4 triangles on the sides of the quadrilateral ABCD
= 1/2(2)(1) + 1/2(1)(2) + 1/2(2)(1) + 1/2(1)(2) = 4 units²
∴ The area of quadrilateral ABCD = 9 - 4 = 5 units²