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Finding the Fourth Proportional to 101.78, 139.89 and 98.90

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Solution

The fourth proportional to 101.78, 139.89 and 98.90 is: 135.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.78 : 139.89 = 98.90 : x
  2. Step 2: Convert to fraction form
    101.78/139.89 = 98.90/x
  3. Step 3: Cross multiply
    101.78x = 139.89 × 98.90
  4. Step 4: Simplify right side
    101.78x = 13,834.63
  5. Step 5: Solve for x
    x = 13,834.63/101.78
  6. Step 6: Final answer
    x = 135.93

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.