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Finding the Fourth Proportional to 688.21, 948.34 and 491.38

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Solution

The fourth proportional to 688.21, 948.34 and 491.38 is: 677.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.21 : 948.34 = 491.38 : x
  2. Step 2: Convert to fraction form
    688.21/948.34 = 491.38/x
  3. Step 3: Cross multiply
    688.21x = 948.34 × 491.38
  4. Step 4: Simplify right side
    688.21x = 465,993.55
  5. Step 5: Solve for x
    x = 465,993.55/688.21
  6. Step 6: Final answer
    x = 677.11

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Half scale
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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.