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Finding the Fourth Proportional to 81.60, 112.40 and 64.32

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Solution

The fourth proportional to 81.60, 112.40 and 64.32 is: 88.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.60 : 112.40 = 64.32 : x
  2. Step 2: Convert to fraction form
    81.60/112.40 = 64.32/x
  3. Step 3: Cross multiply
    81.60x = 112.40 × 64.32
  4. Step 4: Simplify right side
    81.60x = 7,229.57
  5. Step 5: Solve for x
    x = 7,229.57/81.60
  6. Step 6: Final answer
    x = 88.60

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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.