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Finding the Fourth Proportional to 103.45, 142.75 and 87.05

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Solution

The fourth proportional to 103.45, 142.75 and 87.05 is: 120.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.45 : 142.75 = 87.05 : x
  2. Step 2: Convert to fraction form
    103.45/142.75 = 87.05/x
  3. Step 3: Cross multiply
    103.45x = 142.75 × 87.05
  4. Step 4: Simplify right side
    103.45x = 12,426.39
  5. Step 5: Solve for x
    x = 12,426.39/103.45
  6. Step 6: Final answer
    x = 120.12

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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.