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Finding the Fourth Proportional to 431.16, 641.25 and 418.20

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Solution

The fourth proportional to 431.16, 641.25 and 418.20 is: 621.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.16 : 641.25 = 418.20 : x
  2. Step 2: Convert to fraction form
    431.16/641.25 = 418.20/x
  3. Step 3: Cross multiply
    431.16x = 641.25 × 418.20
  4. Step 4: Simplify right side
    431.16x = 268,170.75
  5. Step 5: Solve for x
    x = 268,170.75/431.16
  6. Step 6: Final answer
    x = 621.98

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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.