Formulas for volume and surface area of 3D shapes
📦 1. Prisms (e.g. cuboid)
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🔹 Volume
Volume=base area×height\text{Volume} = \text{base area} \times \text{height}Volume=base area×height
For a cuboid:
V=lĂ—wĂ—hV = l \times w \times hV=lĂ—wĂ—h
🔹 Surface Area
Add all the faces:
For cuboid:
SA=2(lw+lh+wh)SA = 2(lw + lh + wh)SA=2(lw+lh+wh)
🔺 2. Pyramid
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🔹 Volume
V=13×base area×heightV = \frac{1}{3} \times \text{base area} \times \text{height}V=31​×base area×height
🔹 Surface Area
SA=base area+triangular facesSA = \text{base area} + \text{triangular faces}SA=base area+triangular faces
(You usually need slant height)
🥫 3. Cylinder
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🔹 Volume
V=Ď€r2hV = \pi r^2 hV=Ď€r2h
🔹 Surface Area
SA=2Ď€r2+2Ď€rhSA = 2\pi r^2 + 2\pi rhSA=2Ď€r2+2Ď€rh
(top + bottom + curved surface)
🍦 4. Cone
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🔹 Volume
V=13πr2hV = \frac{1}{3}\pi r^2 hV=31​πr2h
🔹 Surface Area
SA=Ď€r2+Ď€rlSA = \pi r^2 + \pi rlSA=Ď€r2+Ď€rl
(where l = slant height)
⚡ THE IMPORTANT PART (Science link)
📊 Surface Area to Volume Ratio (SA:V)
👉 This is what your science test really cares about
SA:V=surface areavolume\text{SA:V} = \frac{\text{surface area}}{\text{volume}}SA:V=volumesurface area​