Geometry and Volume Study Guide: Rectangular Prisms, Pyramids, and Compound Solids

Square Pyramid Surface Area Calculation

  • Given Dimensions:     * The base of the net is a square with side lengths of 3m3\,\text{m}.     * The net consists of four identical triangular faces that meet at a point when assembled.     * The slant height (the height of each triangular face) is 5m5\,\text{m}.

  • Surface Area Components:     * Base Area (Square): Calculated using the formula Abase=s2A_{\text{base}} = s^2.         * 3m×3m=9m23\,\text{m} \times 3\,\text{m} = 9\,\text{m}^2     * Lateral Area (Four Triangles): Calculated using the formula for the area of a triangle Atriangle=12×b×hA_{\text{triangle}} = \frac{1}{2} \times b \times h.         * Area of one triangle: 12×3m×5m=7.5m2\frac{1}{2} \times 3\,\text{m} \times 5\,\text{m} = 7.5\,\text{m}^2         * Total lateral area: 4×7.5m2=30m24 \times 7.5\,\text{m}^2 = 30\,\text{m}^2

  • Total Surface Area:     * Total Area=Base Area+Lateral Area\text{Total Area} = \text{Base Area} + \text{Lateral Area}     * 9m2+30m2=39m29\,\text{m}^2 + 30\,\text{m}^2 = 39\,\text{m}^2

Volume of a Right Rectangular Prism (Example 1)

  • Given Dimensions:     * Width: 4in4\,\text{in}     * Height: 13in13\,\text{in}     * Length: 10in10\,\text{in}

  • Volume Formula: V=l×w×hV = l \times w \times h

  • Calculation:     * 10in×4in×13in10\,\text{in} \times 4\,\text{in} \times 13\,\text{in}     * 40in2×13in=520in340\,\text{in}^2 \times 13\,\text{in} = 520\,\text{in}^3

Container and Cube Volume Analysis

  • Rectangular Container Specifications:     * Height: 20cm20\,\text{cm}     * Base Dimensions: 4cm×8cm4\,\text{cm} \times 8\,\text{cm}     * Volume Calculation: 20cm×4cm×8cm=640cm320\,\text{cm} \times 4\,\text{cm} \times 8\,\text{cm} = 640\,\text{cm}^3

  • Cube Toy Specifications:     * Edge length: 4cm4\,\text{cm}     * Volume Calculation: V=s3=4cm×4cm×4cm=64cm3V = s^3 = 4\,\text{cm} \times 4\,\text{cm} \times 4\,\text{cm} = 64\,\text{cm}^3

  • Quantity of Toys within Container:     * To find how many toys fit, divide the total container volume by the volume of one cube.     * 640cm364cm3=10toys\frac{640\,\text{cm}^3}{64\,\text{cm}^3} = 10\,\text{toys}

Area of Rhombus ABCD

  • Given Data:     * The rhombus is composed of four congruent right triangles defined by diagonals intersecting at a central point.     * Horizontal semi-diagonal: 6cm6\,\text{cm}     * Vertical semi-diagonal: 4cm4\,\text{cm}

  • Calculation Method:     * Total horizontal diagonal (d1d_1): 6cm+6cm=12cm6\,\text{cm} + 6\,\text{cm} = 12\,\text{cm}     * Total vertical diagonal (d2d_2): 4cm+4cm=8cm4\,\text{cm} + 4\,\text{cm} = 8\,\text{cm}     * Area Formula: A=d1×d22A = \frac{d_1 \times d_2}{2}     * Calculation: 12cm×8cm2=48cm2\frac{12\,\text{cm} \times 8\,\text{cm}}{2} = 48\,\text{cm}^2

Gift Box Surface Area and Ribbon Length

  • Box Specifications:     * The provided net indicates the box is a cube with side lengths of 5in5\,\text{in}.

  • Part A: Surface Area (Total area covered by paint):     * A cube has 66 identical square faces.     * Area of one face: 5in×5in=25in25\,\text{in} \times 5\,\text{in} = 25\,\text{in}^2     * Total surface area: 6×25in2=150in26 \times 25\,\text{in}^2 = 150\,\text{in}^2

  • Part B: Total Edge Length (Ribbon calculation):     * A cube has 1212 edges.     * Total inches of ribbon: 12×5in=60in12 \times 5\,\text{in} = 60\,\text{in}     * Conversion to feet: Since 12in=1ft12\,\text{in} = 1\,\text{ft}, 60in12in/ft=5ft\frac{60\,\text{in}}{12\,\text{in/ft}} = 5\,\text{ft}.

Composite Volume of Two Right Rectangular Prisms

  • Structure Description: The solid is formed by two joined prisms.

  • Prism 1 (Left):     * Dimensions: 6ft×3ft×412ft6\,\text{ft} \times 3\,\text{ft} \times 4\frac{1}{2}\,\text{ft}     * Fractional conversion: 412=4.54\frac{1}{2} = 4.5     * Volume: 6ft×3ft×4.5ft=81ft36\,\text{ft} \times 3\,\text{ft} \times 4.5\,\text{ft} = 81\,\text{ft}^3

  • Prism 2 (Right):     * Dimensions: 9ft×10ft×412ft9\,\text{ft} \times 10\,\text{ft} \times 4\frac{1}{2}\,\text{ft}     * Volume: 9ft×10ft×4.5ft=405ft39\,\text{ft} \times 10\,\text{ft} \times 4.5\,\text{ft} = 405\,\text{ft}^3

  • Total Volume:     * 81ft3+405ft3=486ft381\,\text{ft}^3 + 405\,\text{ft}^3 = 486\,\text{ft}^3

Area of a Trapezoid

  • Given Dimensions:     * Base 1 (b1b_1): 19cm19\,\text{cm}     * Base 2 (b2b_2): 11cm11\,\text{cm}     * Height (hh): 15cm15\,\text{cm}     * Slant side length: 13cm13\,\text{cm}

  • Area Formula: A=b1+b22×hA = \frac{b_1 + b_2}{2} \times h

  • Calculation:     * 19cm+11cm2×15cm\frac{19\,\text{cm} + 11\,\text{cm}}{2} \times 15\,\text{cm}     * 30cm2×15cm=15cm×15cm=225cm2\frac{30\,\text{cm}}{2} \times 15\,\text{cm} = 15\,\text{cm} \times 15\,\text{cm} = 225\,\text{cm}^2

Volume of a Right Rectangular Prism (Example 2)

  • Given Dimensions:     * Length: 14in14\,\text{in}     * Width: 8in8\,\text{in}     * Height: 5in5\,\text{in}     * Additional value provided in figure: 35in35\,\text{in} (Context suggests this might be the area of one face, but standard volume requires the three primary edges).

  • Calculation:     * V=14in×8in×5inV = 14\,\text{in} \times 8\,\text{in} \times 5\,\text{in}     * 14in×40in2=560in314\,\text{in} \times 40\,\text{in}^2 = 560\,\text{in}^3