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Finding the Fourth Proportional to 418.40, 624.28 and 415.72

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Solution

The fourth proportional to 418.40, 624.28 and 415.72 is: 620.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    418.40 : 624.28 = 415.72 : x
  2. Step 2: Convert to fraction form
    418.40/624.28 = 415.72/x
  3. Step 3: Cross multiply
    418.40x = 624.28 × 415.72
  4. Step 4: Simplify right side
    418.40x = 259,525.68
  5. Step 5: Solve for x
    x = 259,525.68/418.40
  6. Step 6: Final answer
    x = 620.28

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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.