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Finding the Fourth Proportional to 665.28, 918.07 and 399.88

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Solution

The fourth proportional to 665.28, 918.07 and 399.88 is: 551.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.28 : 918.07 = 399.88 : x
  2. Step 2: Convert to fraction form
    665.28/918.07 = 399.88/x
  3. Step 3: Cross multiply
    665.28x = 918.07 × 399.88
  4. Step 4: Simplify right side
    665.28x = 367,114.54
  5. Step 5: Solve for x
    x = 367,114.54/665.28
  6. Step 6: Final answer
    x = 551.82

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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.