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Finding the Fourth Proportional to 781.25, 1,078.26 and 470.75

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Solution

The fourth proportional to 781.25, 1,078.26 and 470.75 is: 649.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.25 : 1,078.26 = 470.75 : x
  2. Step 2: Convert to fraction form
    781.25/1,078.26 = 470.75/x
  3. Step 3: Cross multiply
    781.25x = 1,078.26 × 470.75
  4. Step 4: Simplify right side
    781.25x = 507,590.90
  5. Step 5: Solve for x
    x = 507,590.90/781.25
  6. Step 6: Final answer
    x = 649.72

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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.