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Finding the Fourth Proportional to 781.48, 1,078.50 and 486.76

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Solution

The fourth proportional to 781.48, 1,078.50 and 486.76 is: 671.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.48 : 1,078.50 = 486.76 : x
  2. Step 2: Convert to fraction form
    781.48/1,078.50 = 486.76/x
  3. Step 3: Cross multiply
    781.48x = 1,078.50 × 486.76
  4. Step 4: Simplify right side
    781.48x = 524,970.66
  5. Step 5: Solve for x
    x = 524,970.66/781.48
  6. Step 6: Final answer
    x = 671.76

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Double scale
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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.