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Finding the Fourth Proportional to 781.12, 1,077.64 and 501.31

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Solution

The fourth proportional to 781.12, 1,077.64 and 501.31 is: 691.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.12 : 1,077.64 = 501.31 : x
  2. Step 2: Convert to fraction form
    781.12/1,077.64 = 501.31/x
  3. Step 3: Cross multiply
    781.12x = 1,077.64 × 501.31
  4. Step 4: Simplify right side
    781.12x = 540,236.95
  5. Step 5: Solve for x
    x = 540,236.95/781.12
  6. Step 6: Final answer
    x = 691.62

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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.