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Finding the Fourth Proportional to 666.99, 920.43 and 387.09

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Solution

The fourth proportional to 666.99, 920.43 and 387.09 is: 534.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.99 : 920.43 = 387.09 : x
  2. Step 2: Convert to fraction form
    666.99/920.43 = 387.09/x
  3. Step 3: Cross multiply
    666.99x = 920.43 × 387.09
  4. Step 4: Simplify right side
    666.99x = 356,289.25
  5. Step 5: Solve for x
    x = 356,289.25/666.99
  6. Step 6: Final answer
    x = 534.17

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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.