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Finding the Fourth Proportional to 431.33, 647.22 and 138.88

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Solution

The fourth proportional to 431.33, 647.22 and 138.88 is: 208.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.33 : 647.22 = 138.88 : x
  2. Step 2: Convert to fraction form
    431.33/647.22 = 138.88/x
  3. Step 3: Cross multiply
    431.33x = 647.22 × 138.88
  4. Step 4: Simplify right side
    431.33x = 89,887.24
  5. Step 5: Solve for x
    x = 89,887.24/431.33
  6. Step 6: Final answer
    x = 208.40

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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.