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Finding the Fourth Proportional to 91.21, 125.76 and 76.48

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Solution

The fourth proportional to 91.21, 125.76 and 76.48 is: 105.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.21 : 125.76 = 76.48 : x
  2. Step 2: Convert to fraction form
    91.21/125.76 = 76.48/x
  3. Step 3: Cross multiply
    91.21x = 125.76 × 76.48
  4. Step 4: Simplify right side
    91.21x = 9,618.12
  5. Step 5: Solve for x
    x = 9,618.12/91.21
  6. Step 6: Final answer
    x = 105.45

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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.