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Triangular Prism: Volume and Surface Area

May 4, 2025

Lecture on Volume and Surface Area of a Triangular Prism

Introduction

  • Topic: Calculating the volume and surface area of a triangular prism.
  • Initial comparison with a rectangular prism to understand the concept.

Volume of a Triangular Prism

  • Understanding the Shape: A triangular prism is essentially half of a rectangular prism.
  • Formula for Volume:
    • Volume = 1/2 × Base Area × Height of the prism
    • Base Area (triangle) = 1/2 × base × height
    • Volume = 1/2 × (base of triangle) × (height of triangle) × (length/prism height)

Surface Area of a Triangular Prism

  • Components:
    • Surface Area = Base Area + Lateral Area
    • Base Area = 2 × (1/2 × base × height) = base × height (for both triangles)
    • Lateral Area = Perimeter of triangular base × length of the prism
  • Finding Perimeter:
    • Perimeter = base + height + hypotenuse (Pythagorean theorem if necessary)
  • Final Formula for Surface Area:
    • Surface Area = base × height + perimeter × length of the prism

Example Calculations

  • Example 1:

    • Given: Length = 6 in, Base = 3 in, Height = 4 in
    • Volume Calculation: 1/2 × 3 × 4 × 6 = 36 cubic inches
    • Hypotenuse Calculation: C = 5 in (using Pythagorean theorem)
    • Surface Area Calculation: Perimeter = 12 in, Surface Area = 84 square inches
  • Example 2:

    • Given: Length = 10 cm, Base = 5 cm, Height = 4 cm
    • Volume Calculation: 1/2 × 5 × 4 × 10 = 100 cubic cm
  • Example 3:

    • Given: Length = 15 units, Base = 6 units, Triangle sides = 6, 8, and 10
    • Surface Area: Perimeter = 24 units, Surface Area = 408 square units
    • Volume Calculation: Volume = 360 cubic units

Practice Problems

  • Additional examples to find volume and surface area of various triangular prisms using given dimensions.

Key Concepts Recap

  • Understand and differentiate between base, height, and length of the prism.
  • Apply Pythagorean theorem for calculating missing dimensions in right triangles.
  • Recognize when to calculate only lateral area.
  • Ensure proper units: surface area in square units, volume in cubic units.

Additional Resources

  • Mention of an algebra course available on Udemy for further learning on related mathematics topics.