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Finding the Fourth Proportional to 113.28, 156 and 100.80

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Solution

The fourth proportional to 113.28, 156 and 100.80 is: 138.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    113.28 : 156 = 100.80 : x
  2. Step 2: Convert to fraction form
    113.28/156 = 100.80/x
  3. Step 3: Cross multiply
    113.28x = 156 × 100.80
  4. Step 4: Simplify right side
    113.28x = 15,724.80
  5. Step 5: Solve for x
    x = 15,724.80/113.28
  6. Step 6: Final answer
    x = 138.81

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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.