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Finding the Fourth Proportional to 86.47, 129.57 and 64.70

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Solution

The fourth proportional to 86.47, 129.57 and 64.70 is: 96.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.47 : 129.57 = 64.70 : x
  2. Step 2: Convert to fraction form
    86.47/129.57 = 64.70/x
  3. Step 3: Cross multiply
    86.47x = 129.57 × 64.70
  4. Step 4: Simplify right side
    86.47x = 8,383.26
  5. Step 5: Solve for x
    x = 8,383.26/86.47
  6. Step 6: Final answer
    x = 96.95

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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.