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Finding the Fourth Proportional to 103.68, 142.29 and 100.91

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Solution

The fourth proportional to 103.68, 142.29 and 100.91 is: 138.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.68 : 142.29 = 100.91 : x
  2. Step 2: Convert to fraction form
    103.68/142.29 = 100.91/x
  3. Step 3: Cross multiply
    103.68x = 142.29 × 100.91
  4. Step 4: Simplify right side
    103.68x = 14,358.84
  5. Step 5: Solve for x
    x = 14,358.84/103.68
  6. Step 6: Final answer
    x = 138.49

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.