Triangular Prisms and the "Rectangle Trap"
Triangular Prisms and the "Rectangle Trap" is a skill on Pengi from Section 14.1: Surface Areas of Prisms in Big Ideas Math, Advanced 2.
Key Concepts
Property A triangular prism has exactly 5 faces: 2 identical triangular bases and 3 rectangular sides . To find the total surface area, find the area of the 2 triangles and the 3 rectangles, then add them together.
Examples The Trap: A triangular prism has a triangle base with sides of 3 cm, 4 cm, and 5 cm. The height of the whole prism is 10 cm. You will have 3 DIFFERENT rectangles: Rectangle 1: 3 x 10 = 30 sq cm Rectangle 2: 4 x 10 = 40 sq cm Rectangle 3: 5 x 10 = 50 sq cm (Plus the area of the two triangles!).
Explanation Beware of the biggest trap in 7th grade geometry! Many students assume the 3 rectangular sides of a triangular prism are always identical. They are NOT! The width of each rectangle connects to a side of the triangle. Unless the triangle is perfectly equilateral (all 3 sides equal), those three rectangular faces will be completely different sizes. Always unfold it into a net in your mind first!
Common Questions
What is Triangular Prisms and the "Rectangle Trap"?
Triangular Prisms and the "Rectangle Trap" is a skill on Pengi from Section 14.1: Surface Areas of Prisms in Big Ideas Math, Advanced 2.
What grade level is Triangular Prisms and the "Rectangle Trap" for?
Triangular Prisms and the "Rectangle Trap" is part of the Grade 7 Math curriculum, covered in Big Ideas Math, Advanced 2. It is designed for students studying Math at the Grade 7 level.
How can I learn Triangular Prisms and the "Rectangle Trap"?
Pengi offers an AI-guided lesson for Triangular Prisms and the "Rectangle Trap" that walks you through the key concepts step by step. The lesson is aligned to Big Ideas Math, Advanced 2 so the content matches what you see in class.
How do I practice Triangular Prisms and the "Rectangle Trap"?
After learning the concept, use the Practice mode to work through targeted exercises on Triangular Prisms and the "Rectangle Trap". The AI adapts to your level and gives feedback on each answer so you can identify and fix mistakes.
Which textbook covers Triangular Prisms and the "Rectangle Trap"?
Triangular Prisms and the "Rectangle Trap" is covered in Big Ideas Math, Advanced 2, specifically in Chapter 14: Surface Area and Volume under Section 14.1: Surface Areas of Prisms. Pengi's lesson is aligned directly to this textbook so you can follow along with your class.
Is Triangular Prisms and the "Rectangle Trap" free to study on Pengi?
Yes, the core Learn and Practice modes for Triangular Prisms and the "Rectangle Trap" are available for free on Pengi. No credit card is required to start studying.