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Finding the Fourth Proportional to 91.26, 125.28 and 78.30

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Solution

The fourth proportional to 91.26, 125.28 and 78.30 is: 107.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.26 : 125.28 = 78.30 : x
  2. Step 2: Convert to fraction form
    91.26/125.28 = 78.30/x
  3. Step 3: Cross multiply
    91.26x = 125.28 × 78.30
  4. Step 4: Simplify right side
    91.26x = 9,809.42
  5. Step 5: Solve for x
    x = 9,809.42/91.26
  6. Step 6: Final answer
    x = 107.49

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.