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Finding the Fourth Proportional to 86.20, 118.96 and 47.39

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Solution

The fourth proportional to 86.20, 118.96 and 47.39 is: 65.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.20 : 118.96 = 47.39 : x
  2. Step 2: Convert to fraction form
    86.20/118.96 = 47.39/x
  3. Step 3: Cross multiply
    86.20x = 118.96 × 47.39
  4. Step 4: Simplify right side
    86.20x = 5,637.60
  5. Step 5: Solve for x
    x = 5,637.60/86.20
  6. Step 6: Final answer
    x = 65.40

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.