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Finding the Fourth Proportional to 665.72, 918.54 and 385.86

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Solution

The fourth proportional to 665.72, 918.54 and 385.86 is: 532.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.72 : 918.54 = 385.86 : x
  2. Step 2: Convert to fraction form
    665.72/918.54 = 385.86/x
  3. Step 3: Cross multiply
    665.72x = 918.54 × 385.86
  4. Step 4: Simplify right side
    665.72x = 354,431.29
  5. Step 5: Solve for x
    x = 354,431.29/665.72
  6. Step 6: Final answer
    x = 532.40

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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.