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Finding the Fourth Proportional to 88.39, 121.64 and 81.88

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Solution

The fourth proportional to 88.39, 121.64 and 81.88 is: 112.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.39 : 121.64 = 81.88 : x
  2. Step 2: Convert to fraction form
    88.39/121.64 = 81.88/x
  3. Step 3: Cross multiply
    88.39x = 121.64 × 81.88
  4. Step 4: Simplify right side
    88.39x = 9,959.17
  5. Step 5: Solve for x
    x = 9,959.17/88.39
  6. Step 6: Final answer
    x = 112.67

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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.