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Finding the Fourth Proportional to 665.20, 917.75 and 385.30

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Solution

The fourth proportional to 665.20, 917.75 and 385.30 is: 531.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.20 : 917.75 = 385.30 : x
  2. Step 2: Convert to fraction form
    665.20/917.75 = 385.30/x
  3. Step 3: Cross multiply
    665.20x = 917.75 × 385.30
  4. Step 4: Simplify right side
    665.20x = 353,602.56
  5. Step 5: Solve for x
    x = 353,602.56/665.20
  6. Step 6: Final answer
    x = 531.58

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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.