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Finding the Fourth Proportional to 90.99, 125.42 and 71.28

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Solution

The fourth proportional to 90.99, 125.42 and 71.28 is: 98.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.99 : 125.42 = 71.28 : x
  2. Step 2: Convert to fraction form
    90.99/125.42 = 71.28/x
  3. Step 3: Cross multiply
    90.99x = 125.42 × 71.28
  4. Step 4: Simplify right side
    90.99x = 8,939.58
  5. Step 5: Solve for x
    x = 8,939.58/90.99
  6. Step 6: Final answer
    x = 98.25

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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.