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Finding the Fourth Proportional to 431.83, 647.78 and 212.57

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Solution

The fourth proportional to 431.83, 647.78 and 212.57 is: 318.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.83 : 647.78 = 212.57 : x
  2. Step 2: Convert to fraction form
    431.83/647.78 = 212.57/x
  3. Step 3: Cross multiply
    431.83x = 647.78 × 212.57
  4. Step 4: Simplify right side
    431.83x = 137,701.56
  5. Step 5: Solve for x
    x = 137,701.56/431.83
  6. Step 6: Final answer
    x = 318.88

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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.