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Finding the Fourth Proportional to 147.28, 220.85 and 86.43

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Solution

The fourth proportional to 147.28, 220.85 and 86.43 is: 129.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    147.28 : 220.85 = 86.43 : x
  2. Step 2: Convert to fraction form
    147.28/220.85 = 86.43/x
  3. Step 3: Cross multiply
    147.28x = 220.85 × 86.43
  4. Step 4: Simplify right side
    147.28x = 19,088.07
  5. Step 5: Solve for x
    x = 19,088.07/147.28
  6. Step 6: Final answer
    x = 129.60

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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.