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Finding the Fourth Proportional to 665.12, 917.64 and 385.28

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Solution

The fourth proportional to 665.12, 917.64 and 385.28 is: 531.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.12 : 917.64 = 385.28 : x
  2. Step 2: Convert to fraction form
    665.12/917.64 = 385.28/x
  3. Step 3: Cross multiply
    665.12x = 917.64 × 385.28
  4. Step 4: Simplify right side
    665.12x = 353,548.34
  5. Step 5: Solve for x
    x = 353,548.34/665.12
  6. Step 6: Final answer
    x = 531.56

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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.