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Finding the Fourth Proportional to 421.64, 631.68 and 215.88

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Solution

The fourth proportional to 421.64, 631.68 and 215.88 is: 323.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.64 : 631.68 = 215.88 : x
  2. Step 2: Convert to fraction form
    421.64/631.68 = 215.88/x
  3. Step 3: Cross multiply
    421.64x = 631.68 × 215.88
  4. Step 4: Simplify right side
    421.64x = 136,367.08
  5. Step 5: Solve for x
    x = 136,367.08/421.64
  6. Step 6: Final answer
    x = 323.42

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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.