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Finding the Fourth Proportional to 661.88, 913.38 and 399.92

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Solution

The fourth proportional to 661.88, 913.38 and 399.92 is: 551.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.88 : 913.38 = 399.92 : x
  2. Step 2: Convert to fraction form
    661.88/913.38 = 399.92/x
  3. Step 3: Cross multiply
    661.88x = 913.38 × 399.92
  4. Step 4: Simplify right side
    661.88x = 365,278.93
  5. Step 5: Solve for x
    x = 365,278.93/661.88
  6. Step 6: Final answer
    x = 551.88

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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.