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Finding the Fourth Proportional to 103.79, 156.31 and 90.43

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Solution

The fourth proportional to 103.79, 156.31 and 90.43 is: 136.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.79 : 156.31 = 90.43 : x
  2. Step 2: Convert to fraction form
    103.79/156.31 = 90.43/x
  3. Step 3: Cross multiply
    103.79x = 156.31 × 90.43
  4. Step 4: Simplify right side
    103.79x = 14,134.50
  5. Step 5: Solve for x
    x = 14,134.50/103.79
  6. Step 6: Final answer
    x = 136.18

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.