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Finding the Fourth Proportional to 431.70, 647.22 and 215.43

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Solution

The fourth proportional to 431.70, 647.22 and 215.43 is: 322.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.70 : 647.22 = 215.43 : x
  2. Step 2: Convert to fraction form
    431.70/647.22 = 215.43/x
  3. Step 3: Cross multiply
    431.70x = 647.22 × 215.43
  4. Step 4: Simplify right side
    431.70x = 139,430.60
  5. Step 5: Solve for x
    x = 139,430.60/431.70
  6. Step 6: Final answer
    x = 322.98

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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.