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Finding the Fourth Proportional to 90.64, 125.28 and 81.52

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Solution

The fourth proportional to 90.64, 125.28 and 81.52 is: 112.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.64 : 125.28 = 81.52 : x
  2. Step 2: Convert to fraction form
    90.64/125.28 = 81.52/x
  3. Step 3: Cross multiply
    90.64x = 125.28 × 81.52
  4. Step 4: Simplify right side
    90.64x = 10,212.83
  5. Step 5: Solve for x
    x = 10,212.83/90.64
  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.