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Finding the Fourth Proportional to 421.10, 631.36 and 215.28

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Solution

The fourth proportional to 421.10, 631.36 and 215.28 is: 322.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.10 : 631.36 = 215.28 : x
  2. Step 2: Convert to fraction form
    421.10/631.36 = 215.28/x
  3. Step 3: Cross multiply
    421.10x = 631.36 × 215.28
  4. Step 4: Simplify right side
    421.10x = 135,919.18
  5. Step 5: Solve for x
    x = 135,919.18/421.10
  6. Step 6: Final answer
    x = 322.77

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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.