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Finding the Fourth Proportional to 103.68, 143.18 and 87.11

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Solution

The fourth proportional to 103.68, 143.18 and 87.11 is: 120.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.68 : 143.18 = 87.11 : x
  2. Step 2: Convert to fraction form
    103.68/143.18 = 87.11/x
  3. Step 3: Cross multiply
    103.68x = 143.18 × 87.11
  4. Step 4: Simplify right side
    103.68x = 12,471.26
  5. Step 5: Solve for x
    x = 12,471.26/103.68
  6. Step 6: Final answer
    x = 120.29

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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.