Surface area of a triangular prism calculated by summing the areas of all faces, with example dimensions and calculations.

Let’s solve this step by step.

We are finding the surface area of a triangular prism. That means we need to add up the areas of all its faces.

The prism has 5 faces:
- Front triangle
- Back triangle (same as front)
- Bottom rectangle
- Left side rectangle
- Right side rectangle

From the diagram and table:

✔ Front face: It’s a right triangle with base = 3 cm, height = 4 cm
Area = ½ × base × height = ½ × 3 × 4 = 6 cm²

✔ Back face: Same as front → also 6 cm²

✔ Bottom face: Rectangle with sides 3 cm and 9 cm
Area = 3 × 9 = 27 cm²

✔ Left side face: Rectangle with sides 4 cm and 9 cm
Area = 4 × 9 = 36 cm²

✔ Right side face: Rectangle with sides 5 cm and 9 cm
Area = 5 × 9 = 45 cm²

Now, add them all together:

6 + 6 = 12
12 + 27 = 39
39 + 36 = 75
75 + 45 = 120

So total surface area = 120 cm²

Final Answer:
120 cm²