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Finding the Fourth Proportional to 542.80, 815.16 and 420.69

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Solution

The fourth proportional to 542.80, 815.16 and 420.69 is: 631.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    542.80 : 815.16 = 420.69 : x
  2. Step 2: Convert to fraction form
    542.80/815.16 = 420.69/x
  3. Step 3: Cross multiply
    542.80x = 815.16 × 420.69
  4. Step 4: Simplify right side
    542.80x = 342,934.29
  5. Step 5: Solve for x
    x = 342,934.29/542.80
  6. Step 6: Final answer
    x = 631.79

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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.