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Finding the Fourth Proportional to 100.96, 138.56 and 90.04

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Solution

The fourth proportional to 100.96, 138.56 and 90.04 is: 123.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.96 : 138.56 = 90.04 : x
  2. Step 2: Convert to fraction form
    100.96/138.56 = 90.04/x
  3. Step 3: Cross multiply
    100.96x = 138.56 × 90.04
  4. Step 4: Simplify right side
    100.96x = 12,475.94
  5. Step 5: Solve for x
    x = 12,475.94/100.96
  6. Step 6: Final answer
    x = 123.57

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.