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Finding the Fourth Proportional to 100.36, 138.54 and 75.80

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Solution

The fourth proportional to 100.36, 138.54 and 75.80 is: 104.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.36 : 138.54 = 75.80 : x
  2. Step 2: Convert to fraction form
    100.36/138.54 = 75.80/x
  3. Step 3: Cross multiply
    100.36x = 138.54 × 75.80
  4. Step 4: Simplify right side
    100.36x = 10,501.68
  5. Step 5: Solve for x
    x = 10,501.68/100.36
  6. Step 6: Final answer
    x = 104.64

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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.