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Finding the Fourth Proportional to 90.68, 125.09 and 57.42

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Solution

The fourth proportional to 90.68, 125.09 and 57.42 is: 79.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.68 : 125.09 = 57.42 : x
  2. Step 2: Convert to fraction form
    90.68/125.09 = 57.42/x
  3. Step 3: Cross multiply
    90.68x = 125.09 × 57.42
  4. Step 4: Simplify right side
    90.68x = 7,182.38
  5. Step 5: Solve for x
    x = 7,182.38/90.68
  6. Step 6: Final answer
    x = 79.21

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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.