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Finding the Fourth Proportional to 86.55, 129.75 and 75.20

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Solution

The fourth proportional to 86.55, 129.75 and 75.20 is: 112.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.55 : 129.75 = 75.20 : x
  2. Step 2: Convert to fraction form
    86.55/129.75 = 75.20/x
  3. Step 3: Cross multiply
    86.55x = 129.75 × 75.20
  4. Step 4: Simplify right side
    86.55x = 9,756.55
  5. Step 5: Solve for x
    x = 9,756.55/86.55
  6. Step 6: Final answer
    x = 112.73

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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.