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Finding the Fourth Proportional to 431.84, 647.74 and 139.33

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Solution

The fourth proportional to 431.84, 647.74 and 139.33 is: 208.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.84 : 647.74 = 139.33 : x
  2. Step 2: Convert to fraction form
    431.84/647.74 = 139.33/x
  3. Step 3: Cross multiply
    431.84x = 647.74 × 139.33
  4. Step 4: Simplify right side
    431.84x = 90,246.03
  5. Step 5: Solve for x
    x = 90,246.03/431.84
  6. Step 6: Final answer
    x = 208.98

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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.