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Finding the Fourth Proportional to 103.12, 142.35 and 85.84

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Solution

The fourth proportional to 103.12, 142.35 and 85.84 is: 118.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.12 : 142.35 = 85.84 : x
  2. Step 2: Convert to fraction form
    103.12/142.35 = 85.84/x
  3. Step 3: Cross multiply
    103.12x = 142.35 × 85.84
  4. Step 4: Simplify right side
    103.12x = 12,219.32
  5. Step 5: Solve for x
    x = 12,219.32/103.12
  6. Step 6: Final answer
    x = 118.50

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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.