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Finding the Fourth Proportional to 81.51, 112.60 and 65.12

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Solution

The fourth proportional to 81.51, 112.60 and 65.12 is: 89.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.51 : 112.60 = 65.12 : x
  2. Step 2: Convert to fraction form
    81.51/112.60 = 65.12/x
  3. Step 3: Cross multiply
    81.51x = 112.60 × 65.12
  4. Step 4: Simplify right side
    81.51x = 7,331.62
  5. Step 5: Solve for x
    x = 7,331.62/81.51
  6. Step 6: Final answer
    x = 89.95

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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.