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Finding the Fourth Proportional to 100.45, 138.27 and 89.92

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Solution

The fourth proportional to 100.45, 138.27 and 89.92 is: 123.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.45 : 138.27 = 89.92 : x
  2. Step 2: Convert to fraction form
    100.45/138.27 = 89.92/x
  3. Step 3: Cross multiply
    100.45x = 138.27 × 89.92
  4. Step 4: Simplify right side
    100.45x = 12,433.24
  5. Step 5: Solve for x
    x = 12,433.24/100.45
  6. Step 6: Final answer
    x = 123.78

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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.