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Finding the Fourth Proportional to 90.74, 125.33 and 78.45

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Solution

The fourth proportional to 90.74, 125.33 and 78.45 is: 108.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.74 : 125.33 = 78.45 : x
  2. Step 2: Convert to fraction form
    90.74/125.33 = 78.45/x
  3. Step 3: Cross multiply
    90.74x = 125.33 × 78.45
  4. Step 4: Simplify right side
    90.74x = 9,831.75
  5. Step 5: Solve for x
    x = 9,831.75/90.74
  6. Step 6: Final answer
    x = 108.36

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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.