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Finding the Fourth Proportional to 86.28, 129.28 and 45.57

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Solution

The fourth proportional to 86.28, 129.28 and 45.57 is: 68.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.28 : 129.28 = 45.57 : x
  2. Step 2: Convert to fraction form
    86.28/129.28 = 45.57/x
  3. Step 3: Cross multiply
    86.28x = 129.28 × 45.57
  4. Step 4: Simplify right side
    86.28x = 5,891.29
  5. Step 5: Solve for x
    x = 5,891.29/86.28
  6. Step 6: Final answer
    x = 68.28

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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.