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Finding the Fourth Proportional to 687.57, 948.96 and 393

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Solution

The fourth proportional to 687.57, 948.96 and 393 is: 542.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.57 : 948.96 = 393 : x
  2. Step 2: Convert to fraction form
    687.57/948.96 = 393/x
  3. Step 3: Cross multiply
    687.57x = 948.96 × 393
  4. Step 4: Simplify right side
    687.57x = 372,941.28
  5. Step 5: Solve for x
    x = 372,941.28/687.57
  6. Step 6: Final answer
    x = 542.40

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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.