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Finding the Fourth Proportional to 431.63, 647.50 and 139.03

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Solution

The fourth proportional to 431.63, 647.50 and 139.03 is: 208.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.63 : 647.50 = 139.03 : x
  2. Step 2: Convert to fraction form
    431.63/647.50 = 139.03/x
  3. Step 3: Cross multiply
    431.63x = 647.50 × 139.03
  4. Step 4: Simplify right side
    431.63x = 90,020.48
  5. Step 5: Solve for x
    x = 90,020.48/431.63
  6. Step 6: Final answer
    x = 208.56

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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.