Students solve 9 surface area problems, decode their answers, and reveal a secret message — all while practising a key geometry skill! This self-checking, no-prep worksheet is perfect for classwork, early finishers, homework, or a sub plan. Students calculate the surface area of triangular prisms using right triangles and isosceles triangles. Each answer matches a letter in the Answer Decoder, and the completed secret message gives instant self-checking feedback — no teacher marking required. Wh