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Finding the Fourth Proportional to 100.89, 138.99 and 76.32

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Solution

The fourth proportional to 100.89, 138.99 and 76.32 is: 105.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.89 : 138.99 = 76.32 : x
  2. Step 2: Convert to fraction form
    100.89/138.99 = 76.32/x
  3. Step 3: Cross multiply
    100.89x = 138.99 × 76.32
  4. Step 4: Simplify right side
    100.89x = 10,607.72
  5. Step 5: Solve for x
    x = 10,607.72/100.89
  6. Step 6: Final answer
    x = 105.14

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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.