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Finding the Fourth Proportional to 102.60, 142.02 and 99.90

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Solution

The fourth proportional to 102.60, 142.02 and 99.90 is: 138.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.60 : 142.02 = 99.90 : x
  2. Step 2: Convert to fraction form
    102.60/142.02 = 99.90/x
  3. Step 3: Cross multiply
    102.60x = 142.02 × 99.90
  4. Step 4: Simplify right side
    102.60x = 14,187.80
  5. Step 5: Solve for x
    x = 14,187.80/102.60
  6. Step 6: Final answer
    x = 138.28

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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.