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Finding the Fourth Proportional to 86.30, 129.42 and 28.50

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Solution

The fourth proportional to 86.30, 129.42 and 28.50 is: 42.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.30 : 129.42 = 28.50 : x
  2. Step 2: Convert to fraction form
    86.30/129.42 = 28.50/x
  3. Step 3: Cross multiply
    86.30x = 129.42 × 28.50
  4. Step 4: Simplify right side
    86.30x = 3,688.79
  5. Step 5: Solve for x
    x = 3,688.79/86.30
  6. Step 6: Final answer
    x = 42.75

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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.