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Finding the Fourth Proportional to 137.49, 189.43 and 90.78

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Solution

The fourth proportional to 137.49, 189.43 and 90.78 is: 125.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.49 : 189.43 = 90.78 : x
  2. Step 2: Convert to fraction form
    137.49/189.43 = 90.78/x
  3. Step 3: Cross multiply
    137.49x = 189.43 × 90.78
  4. Step 4: Simplify right side
    137.49x = 17,195.75
  5. Step 5: Solve for x
    x = 17,195.75/137.49
  6. Step 6: Final answer
    x = 125.07

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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.