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Finding the Fourth Proportional to 147.80, 221.38 and 86.78

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Solution

The fourth proportional to 147.80, 221.38 and 86.78 is: 129.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    147.80 : 221.38 = 86.78 : x
  2. Step 2: Convert to fraction form
    147.80/221.38 = 86.78/x
  3. Step 3: Cross multiply
    147.80x = 221.38 × 86.78
  4. Step 4: Simplify right side
    147.80x = 19,211.36
  5. Step 5: Solve for x
    x = 19,211.36/147.80
  6. Step 6: Final answer
    x = 129.98

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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.