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Finding the Fourth Proportional to 665.13, 917.91 and 385.45

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Solution

The fourth proportional to 665.13, 917.91 and 385.45 is: 531.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.13 : 917.91 = 385.45 : x
  2. Step 2: Convert to fraction form
    665.13/917.91 = 385.45/x
  3. Step 3: Cross multiply
    665.13x = 917.91 × 385.45
  4. Step 4: Simplify right side
    665.13x = 353,806.11
  5. Step 5: Solve for x
    x = 353,806.11/665.13
  6. Step 6: Final answer
    x = 531.93

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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.