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Finding the Fourth Proportional to 100.19, 138.26 and 72.58

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Solution

The fourth proportional to 100.19, 138.26 and 72.58 is: 100.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.19 : 138.26 = 72.58 : x
  2. Step 2: Convert to fraction form
    100.19/138.26 = 72.58/x
  3. Step 3: Cross multiply
    100.19x = 138.26 × 72.58
  4. Step 4: Simplify right side
    100.19x = 10,034.91
  5. Step 5: Solve for x
    x = 10,034.91/100.19
  6. Step 6: Final answer
    x = 100.16

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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.