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Finding the Fourth Proportional to 661.24, 991.52 and 387.87

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Solution

The fourth proportional to 661.24, 991.52 and 387.87 is: 581.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.24 : 991.52 = 387.87 : x
  2. Step 2: Convert to fraction form
    661.24/991.52 = 387.87/x
  3. Step 3: Cross multiply
    661.24x = 991.52 × 387.87
  4. Step 4: Simplify right side
    661.24x = 384,580.86
  5. Step 5: Solve for x
    x = 384,580.86/661.24
  6. Step 6: Final answer
    x = 581.61

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.