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Finding the Fourth Proportional to 431.91, 647.38 and 212.49

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Solution

The fourth proportional to 431.91, 647.38 and 212.49 is: 318.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.91 : 647.38 = 212.49 : x
  2. Step 2: Convert to fraction form
    431.91/647.38 = 212.49/x
  3. Step 3: Cross multiply
    431.91x = 647.38 × 212.49
  4. Step 4: Simplify right side
    431.91x = 137,561.78
  5. Step 5: Solve for x
    x = 137,561.78/431.91
  6. Step 6: Final answer
    x = 318.50

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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.