2003 AMC 8 Problems/Problem 25

The side lengths of square WXYZ must be 5 cm, since the area is 25 cm ^2. First, you should determine the height of triangle ABC. The distance from O to line WZ must be 2.5 cm, since line WX = 5 cm, and the distance from O to Z is half of that. The distance from line WZ to line BC must be 2, since the side lengths of the small squares are 1, and there are two squares from line WZ to line BC. So, the height of ABC must be 4.5, which is 2.5 + 2. The length of BC can be determined by subtracting 2 from 5, since the length of WZ is 5, and the two squares in the corners give us 2 together. This gives us the base for ABC, which is 3. Then, we multiply 4.5 by 3 and divide by 2, to get an answer of (C) - 27/4.