5.8 Small Group · Group 1
Tier 2 Intervention · Concrete-Representational-Abstract (CRA) · Dual-Language Anchors
Surface Area of Pyramids · Pyramid · Procedural Fluency · Real-World Applications
- Surface area of a pyramid is the base area plus all the triangular side faces. A square pyramid has 1 square base and 4 triangular faces. Each triangle uses the slant height: ½ × base × slant height. We'll walk through a worked example, try one together, then you'll try a few with hints right there when you need them.
- My square pyramid has a 6 in. × 6 in. base and a slant height of 8 in.
- First the base area: 6 × 6 = 36.
- Now one triangular face: ½ × 6 × 8 = 24. A square pyramid has 4 of them, so 4 × 24 = 96.
- I add the base and the side faces: 36 + 96 = 132.
- So the total surface area is 132 in². I used the slant height (8) for the triangles, not the pyramid's height.
- Surface Area of Pyramids (Área de superficie de pirámides) — The total area of a pyramid's base and triangular faces. Formula: SA = B + lateral area.
- Pyramid (Pirámide) — A solid with a flat bottom and triangle sides that meet at one point on top.
- Slant height (Altura inclinada (apotema)) — The height of a side triangle, measured along its slanted face.
- Lateral face (Cara lateral) — A triangle side of a pyramid, not the bottom.
- Base (Base) — The flat bottom of a pyramid.
- Apex (Ápice) — The point at the top of a pyramid where the sides meet.
- A common mistake in Surface Area of Pyramids is finding the four triangular lateral faces correctly (½ × base edge × slant height, times 4) and then stopping — forgetting to add the base area at the end. This leaves the total surface area too small by exactly the base's area. Before you submit, ask: 'Did I add the base area to the four lateral faces, or did I stop after the sides?'
-
1 FILL TABLE
Find the area of one lateral face for each pyramid.
Pyramid Base Edge Slant Height Area of One Face Pyramid 1 Pyramid 2 Pyramid 3 ✏️ Scratchpad / Reasoning -
2 DRAG SORT
Put the steps in order for finding the surface area of a square pyramid (base edge 6, slant height 10).
- Find base area: 6 × 6 = 36
- Find one lateral face: ½ × 6 × 10 = 30
- Multiply by 4 faces: 4 × 30 = 120
- Add base + lateral: 36 + 120
- SA = 156 in²
-
3 MULTIPLE CHOICE
A square pyramid has a base edge of 5 in and a slant height of 7 in. What is the surface area?
- A95 in²
- B70 in²
- C95 in³
- D120 in²
FormulaPut the numbers inWork it outAnswer with its unit- 1Name itWhich measure is asked?
- 2Write the formulaBefore any numbers.
- 3SubstituteMatch each letter.
- 4Unitunits, sq units, or cubic?
-
4 MULTIPLE CHOICE
How many lateral (triangular) faces does a square pyramid have?
- A4
- B3
- C5
- D6
✏️ Workspace & Solution Steps -
5 MULTIPLE CHOICE
What is the area of one triangular face with base 8 in and slant height 6 in?
- A24 in²
- B48 in²
- C14 in²
- D24 in³
FormulaPut the numbers inWork it outAnswer with its unit- 1Name itWhich measure is asked?
- 2Write the formulaBefore any numbers.
- 3SubstituteMatch each letter.
- 4Unitunits, sq units, or cubic?
-
6 ERROR ANALYSIS
Don't Forget the Base
- 1Box:Square pyramid: base edge = 5 in, slant height = 6 in
- 2One Triangular Face:½ × 5 × 6 = 15 in²
- 3Four Faces:4 × 15 = 60 in²
- 4Answer:SA = 60 in² (stopped after the four triangular faces)
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation
Group Discussion Prompt: How does your visual model justify your mathematical solution?
Partner A: "I modeled this by identifying the relationship and..."
Partner B: "I agree with your step because the standard mathematical rule states..."
Complete each sentence stem to demonstrate precise mathematical reasoning:
Writing Task: Justify why your mathematical solution is accurate and complete.