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Finding the Fourth Proportional to 103.65, 142.79 and 85.34

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Solution

The fourth proportional to 103.65, 142.79 and 85.34 is: 117.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.65 : 142.79 = 85.34 : x
  2. Step 2: Convert to fraction form
    103.65/142.79 = 85.34/x
  3. Step 3: Cross multiply
    103.65x = 142.79 × 85.34
  4. Step 4: Simplify right side
    103.65x = 12,184.56
  5. Step 5: Solve for x
    x = 12,184.56/103.65
  6. Step 6: Final answer
    x = 117.55

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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.