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Finding the Fourth Proportional to 416.40, 620.88 and 392.40

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Solution

The fourth proportional to 416.40, 620.88 and 392.40 is: 585.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    416.40 : 620.88 = 392.40 : x
  2. Step 2: Convert to fraction form
    416.40/620.88 = 392.40/x
  3. Step 3: Cross multiply
    416.40x = 620.88 × 392.40
  4. Step 4: Simplify right side
    416.40x = 243,633.31
  5. Step 5: Solve for x
    x = 243,633.31/416.40
  6. Step 6: Final answer
    x = 585.09

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.