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Finding the Fourth Proportional to 101.94, 141.20 and 99.78

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Solution

The fourth proportional to 101.94, 141.20 and 99.78 is: 138.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.94 : 141.20 = 99.78 : x
  2. Step 2: Convert to fraction form
    101.94/141.20 = 99.78/x
  3. Step 3: Cross multiply
    101.94x = 141.20 × 99.78
  4. Step 4: Simplify right side
    101.94x = 14,088.44
  5. Step 5: Solve for x
    x = 14,088.44/101.94
  6. Step 6: Final answer
    x = 138.20

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.