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Finding the Fourth Proportional to 92.87, 128.15 and 72.15

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Solution

The fourth proportional to 92.87, 128.15 and 72.15 is: 99.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.87 : 128.15 = 72.15 : x
  2. Step 2: Convert to fraction form
    92.87/128.15 = 72.15/x
  3. Step 3: Cross multiply
    92.87x = 128.15 × 72.15
  4. Step 4: Simplify right side
    92.87x = 9,245.45
  5. Step 5: Solve for x
    x = 9,245.45/92.87
  6. Step 6: Final answer
    x = 99.55

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.