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Finding the Fourth Proportional to 664.85, 917.15 and 428.74

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Solution

The fourth proportional to 664.85, 917.15 and 428.74 is: 591.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.85 : 917.15 = 428.74 : x
  2. Step 2: Convert to fraction form
    664.85/917.15 = 428.74/x
  3. Step 3: Cross multiply
    664.85x = 917.15 × 428.74
  4. Step 4: Simplify right side
    664.85x = 393,214.45
  5. Step 5: Solve for x
    x = 393,214.45/664.85
  6. Step 6: Final answer
    x = 591.43

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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.