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Finding the Fourth Proportional to 80.90, 111.64 and 77.25

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Solution

The fourth proportional to 80.90, 111.64 and 77.25 is: 106.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.90 : 111.64 = 77.25 : x
  2. Step 2: Convert to fraction form
    80.90/111.64 = 77.25/x
  3. Step 3: Cross multiply
    80.90x = 111.64 × 77.25
  4. Step 4: Simplify right side
    80.90x = 8,624.19
  5. Step 5: Solve for x
    x = 8,624.19/80.90
  6. Step 6: Final answer
    x = 106.60

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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.