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Finding the Fourth Proportional to 431.48, 647.19 and 138.98

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Solution

The fourth proportional to 431.48, 647.19 and 138.98 is: 208.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.48 : 647.19 = 138.98 : x
  2. Step 2: Convert to fraction form
    431.48/647.19 = 138.98/x
  3. Step 3: Cross multiply
    431.48x = 647.19 × 138.98
  4. Step 4: Simplify right side
    431.48x = 89,948.08
  5. Step 5: Solve for x
    x = 89,948.08/431.48
  6. Step 6: Final answer
    x = 208.46

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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.