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Finding the Fourth Proportional to 618.21, 853.14 and 421.79

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Solution

The fourth proportional to 618.21, 853.14 and 421.79 is: 582.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    618.21 : 853.14 = 421.79 : x
  2. Step 2: Convert to fraction form
    618.21/853.14 = 421.79/x
  3. Step 3: Cross multiply
    618.21x = 853.14 × 421.79
  4. Step 4: Simplify right side
    618.21x = 359,841.65
  5. Step 5: Solve for x
    x = 359,841.65/618.21
  6. Step 6: Final answer
    x = 582.07

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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.