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Finding the Fourth Proportional to 103.26, 142.20 and 90.30

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Solution

The fourth proportional to 103.26, 142.20 and 90.30 is: 124.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.26 : 142.20 = 90.30 : x
  2. Step 2: Convert to fraction form
    103.26/142.20 = 90.30/x
  3. Step 3: Cross multiply
    103.26x = 142.20 × 90.30
  4. Step 4: Simplify right side
    103.26x = 12,840.66
  5. Step 5: Solve for x
    x = 12,840.66/103.26
  6. Step 6: Final answer
    x = 124.35

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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.