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Finding the Fourth Proportional to 687.90, 949.31 and 385.07

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Solution

The fourth proportional to 687.90, 949.31 and 385.07 is: 531.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.90 : 949.31 = 385.07 : x
  2. Step 2: Convert to fraction form
    687.90/949.31 = 385.07/x
  3. Step 3: Cross multiply
    687.90x = 949.31 × 385.07
  4. Step 4: Simplify right side
    687.90x = 365,550.80
  5. Step 5: Solve for x
    x = 365,550.80/687.90
  6. Step 6: Final answer
    x = 531.40

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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.