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Finding the Fourth Proportional to 420.16, 576.40 and 408.78

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Solution

The fourth proportional to 420.16, 576.40 and 408.78 is: 560.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.16 : 576.40 = 408.78 : x
  2. Step 2: Convert to fraction form
    420.16/576.40 = 408.78/x
  3. Step 3: Cross multiply
    420.16x = 576.40 × 408.78
  4. Step 4: Simplify right side
    420.16x = 235,620.79
  5. Step 5: Solve for x
    x = 235,620.79/420.16
  6. Step 6: Final answer
    x = 560.79

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.