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Finding the Fourth Proportional to 542.79, 815.40 and 399.42

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Solution

The fourth proportional to 542.79, 815.40 and 399.42 is: 600.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    542.79 : 815.40 = 399.42 : x
  2. Step 2: Convert to fraction form
    542.79/815.40 = 399.42/x
  3. Step 3: Cross multiply
    542.79x = 815.40 × 399.42
  4. Step 4: Simplify right side
    542.79x = 325,687.07
  5. Step 5: Solve for x
    x = 325,687.07/542.79
  6. Step 6: Final answer
    x = 600.02

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.