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Finding the Fourth Proportional to 90.69, 124.86 and 80.84

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Solution

The fourth proportional to 90.69, 124.86 and 80.84 is: 111.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.69 : 124.86 = 80.84 : x
  2. Step 2: Convert to fraction form
    90.69/124.86 = 80.84/x
  3. Step 3: Cross multiply
    90.69x = 124.86 × 80.84
  4. Step 4: Simplify right side
    90.69x = 10,093.68
  5. Step 5: Solve for x
    x = 10,093.68/90.69
  6. Step 6: Final answer
    x = 111.30

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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.