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Finding the Fourth Proportional to 447.09, 616.08 and 390.78

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Solution

The fourth proportional to 447.09, 616.08 and 390.78 is: 538.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    447.09 : 616.08 = 390.78 : x
  2. Step 2: Convert to fraction form
    447.09/616.08 = 390.78/x
  3. Step 3: Cross multiply
    447.09x = 616.08 × 390.78
  4. Step 4: Simplify right side
    447.09x = 240,751.74
  5. Step 5: Solve for x
    x = 240,751.74/447.09
  6. Step 6: Final answer
    x = 538.49

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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.