Matthew made a wooden cube that has an edge length of 9 inches. He painted half the faces of the cube red and the remaining faces yellow. What is the surface area of the faces Matthew painted red?
There are six equal faces. Each face will have area of 9 x 9 = 81 square inches. If half of the faces (so 3 faces) are red, then the total surface area painted red is 3 x 81 = 243 square inches.