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Finding the Fourth Proportional to 102.90, 141.90 and 90.62

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Solution

The fourth proportional to 102.90, 141.90 and 90.62 is: 124.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.90 : 141.90 = 90.62 : x
  2. Step 2: Convert to fraction form
    102.90/141.90 = 90.62/x
  3. Step 3: Cross multiply
    102.90x = 141.90 × 90.62
  4. Step 4: Simplify right side
    102.90x = 12,858.27
  5. Step 5: Solve for x
    x = 12,858.27/102.90
  6. Step 6: Final answer
    x = 124.96

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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.