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Finding the Fourth Proportional to 103.47, 142.89 and 85.23

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Solution

The fourth proportional to 103.47, 142.89 and 85.23 is: 117.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.47 : 142.89 = 85.23 : x
  2. Step 2: Convert to fraction form
    103.47/142.89 = 85.23/x
  3. Step 3: Cross multiply
    103.47x = 142.89 × 85.23
  4. Step 4: Simplify right side
    103.47x = 12,178.51
  5. Step 5: Solve for x
    x = 12,178.51/103.47
  6. Step 6: Final answer
    x = 117.70

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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.