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Finding the Fourth Proportional to 86.30, 129.45 and 53.81

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Solution

The fourth proportional to 86.30, 129.45 and 53.81 is: 80.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.30 : 129.45 = 53.81 : x
  2. Step 2: Convert to fraction form
    86.30/129.45 = 53.81/x
  3. Step 3: Cross multiply
    86.30x = 129.45 × 53.81
  4. Step 4: Simplify right side
    86.30x = 6,965.70
  5. Step 5: Solve for x
    x = 6,965.70/86.30
  6. Step 6: Final answer
    x = 80.72

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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.