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Finding the Fourth Proportional to 100.09, 138.17 and 79.30

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Solution

The fourth proportional to 100.09, 138.17 and 79.30 is: 109.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.09 : 138.17 = 79.30 : x
  2. Step 2: Convert to fraction form
    100.09/138.17 = 79.30/x
  3. Step 3: Cross multiply
    100.09x = 138.17 × 79.30
  4. Step 4: Simplify right side
    100.09x = 10,957.25
  5. Step 5: Solve for x
    x = 10,957.25/100.09
  6. Step 6: Final answer
    x = 109.47

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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.