Official Explanation
To find the area of the shaded rectangular region, you need to multiply the length of the rectangular region by its width. In this question you are given the lengths of three edges: TU=3, UV=4, and VR=2. Note that VR is the length of the shaded rectangle. To find the width of the shaded rectangle, you need to find either RC or VT. Note that VT lies on the front face of the rectangular solid. It is the hypotenuse of right triangle VUT. You know that and UV=4, so TU=3 by the Pythagorean theorem you can conclude that
VT=\(\sqrt{3^2+4^2} =\sqrt{16+9} = \sqrt{25} = 5\). Therefore, the area of the shaded rectangular region is (5)(2) = 10. The correct answer is 10.