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Finding the Fourth Proportional to 687.12, 947.92 and 477.80

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Solution

The fourth proportional to 687.12, 947.92 and 477.80 is: 659.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.12 : 947.92 = 477.80 : x
  2. Step 2: Convert to fraction form
    687.12/947.92 = 477.80/x
  3. Step 3: Cross multiply
    687.12x = 947.92 × 477.80
  4. Step 4: Simplify right side
    687.12x = 452,916.18
  5. Step 5: Solve for x
    x = 452,916.18/687.12
  6. Step 6: Final answer
    x = 659.15

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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.