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Finding the Fourth Proportional to 102.30, 140.85 and 90.31

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Solution

The fourth proportional to 102.30, 140.85 and 90.31 is: 124.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.30 : 140.85 = 90.31 : x
  2. Step 2: Convert to fraction form
    102.30/140.85 = 90.31/x
  3. Step 3: Cross multiply
    102.30x = 140.85 × 90.31
  4. Step 4: Simplify right side
    102.30x = 12,719.59
  5. Step 5: Solve for x
    x = 12,719.59/102.30
  6. Step 6: Final answer
    x = 124.34

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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.