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Finding the Fourth Proportional to 100.77, 138.94 and 63.91

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Solution

The fourth proportional to 100.77, 138.94 and 63.91 is: 88.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.77 : 138.94 = 63.91 : x
  2. Step 2: Convert to fraction form
    100.77/138.94 = 63.91/x
  3. Step 3: Cross multiply
    100.77x = 138.94 × 63.91
  4. Step 4: Simplify right side
    100.77x = 8,879.66
  5. Step 5: Solve for x
    x = 8,879.66/100.77
  6. Step 6: Final answer
    x = 88.12

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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.