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Finding the Fourth Proportional to 100.59, 138.83 and 61.28

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Solution

The fourth proportional to 100.59, 138.83 and 61.28 is: 84.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.59 : 138.83 = 61.28 : x
  2. Step 2: Convert to fraction form
    100.59/138.83 = 61.28/x
  3. Step 3: Cross multiply
    100.59x = 138.83 × 61.28
  4. Step 4: Simplify right side
    100.59x = 8,506.97
  5. Step 5: Solve for x
    x = 8,506.97/100.59
  6. Step 6: Final answer
    x = 84.57

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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.