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Finding the Fourth Proportional to 102.80, 141.78 and 99.62

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Solution

The fourth proportional to 102.80, 141.78 and 99.62 is: 137.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.80 : 141.78 = 99.62 : x
  2. Step 2: Convert to fraction form
    102.80/141.78 = 99.62/x
  3. Step 3: Cross multiply
    102.80x = 141.78 × 99.62
  4. Step 4: Simplify right side
    102.80x = 14,124.12
  5. Step 5: Solve for x
    x = 14,124.12/102.80
  6. Step 6: Final answer
    x = 137.39

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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.