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Finding the Fourth Proportional to 100.28, 138.38 and 58.28

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Solution

The fourth proportional to 100.28, 138.38 and 58.28 is: 80.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.28 : 138.38 = 58.28 : x
  2. Step 2: Convert to fraction form
    100.28/138.38 = 58.28/x
  3. Step 3: Cross multiply
    100.28x = 138.38 × 58.28
  4. Step 4: Simplify right side
    100.28x = 8,064.79
  5. Step 5: Solve for x
    x = 8,064.79/100.28
  6. Step 6: Final answer
    x = 80.42

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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.