Calculate the Total Surface Area of the Triangular Prism Beam
Sipho is helping his uncle build a wooden bookshelf. One of the support beams is in the shape of a right triangular prism to fit neatly under a slanted shelf. The triangular end of the beam has a base of 12 cm, height of 9 cm, the hypotenuse is 15 cm and the length of the beam is 100 cm. He painted the beam evenly, calculating the total surface area in cm² of the wood.