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Finding the Fourth Proportional to 420.74, 631.24 and 215.45

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Solution

The fourth proportional to 420.74, 631.24 and 215.45 is: 323.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.74 : 631.24 = 215.45 : x
  2. Step 2: Convert to fraction form
    420.74/631.24 = 215.45/x
  3. Step 3: Cross multiply
    420.74x = 631.24 × 215.45
  4. Step 4: Simplify right side
    420.74x = 136,000.70
  5. Step 5: Solve for x
    x = 136,000.70/420.74
  6. Step 6: Final answer
    x = 323.24

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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.