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Finding the Fourth Proportional to 781.77, 1,078.89 and 487.14

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Solution

The fourth proportional to 781.77, 1,078.89 and 487.14 is: 672.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.77 : 1,078.89 = 487.14 : x
  2. Step 2: Convert to fraction form
    781.77/1,078.89 = 487.14/x
  3. Step 3: Cross multiply
    781.77x = 1,078.89 × 487.14
  4. Step 4: Simplify right side
    781.77x = 525,564.60
  5. Step 5: Solve for x
    x = 525,564.60/781.77
  6. Step 6: Final answer
    x = 672.27

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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.