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Finding the Fourth Proportional to 421.08, 631.38 and 215.55

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Solution

The fourth proportional to 421.08, 631.38 and 215.55 is: 323.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.08 : 631.38 = 215.55 : x
  2. Step 2: Convert to fraction form
    421.08/631.38 = 215.55/x
  3. Step 3: Cross multiply
    421.08x = 631.38 × 215.55
  4. Step 4: Simplify right side
    421.08x = 136,093.96
  5. Step 5: Solve for x
    x = 136,093.96/421.08
  6. Step 6: Final answer
    x = 323.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.