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Finding the Fourth Proportional to 665.18, 917.78 and 385.40

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Solution

The fourth proportional to 665.18, 917.78 and 385.40 is: 531.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.18 : 917.78 = 385.40 : x
  2. Step 2: Convert to fraction form
    665.18/917.78 = 385.40/x
  3. Step 3: Cross multiply
    665.18x = 917.78 × 385.40
  4. Step 4: Simplify right side
    665.18x = 353,715.67
  5. Step 5: Solve for x
    x = 353,715.67/665.18
  6. Step 6: Final answer
    x = 531.76

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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.