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Finding the Fourth Proportional to 100.91, 139.43 and 79.95

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Solution

The fourth proportional to 100.91, 139.43 and 79.95 is: 110.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.91 : 139.43 = 79.95 : x
  2. Step 2: Convert to fraction form
    100.91/139.43 = 79.95/x
  3. Step 3: Cross multiply
    100.91x = 139.43 × 79.95
  4. Step 4: Simplify right side
    100.91x = 11,147.03
  5. Step 5: Solve for x
    x = 11,147.03/100.91
  6. Step 6: Final answer
    x = 110.47

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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.