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Finding the Fourth Proportional to 420.94, 631.12 and 215.37

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Solution

The fourth proportional to 420.94, 631.12 and 215.37 is: 322.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.94 : 631.12 = 215.37 : x
  2. Step 2: Convert to fraction form
    420.94/631.12 = 215.37/x
  3. Step 3: Cross multiply
    420.94x = 631.12 × 215.37
  4. Step 4: Simplify right side
    420.94x = 135,921.80
  5. Step 5: Solve for x
    x = 135,921.80/420.94
  6. Step 6: Final answer
    x = 322.90

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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.