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Finding the Fourth Proportional to 103.84, 142.94 and 87.40

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Solution

The fourth proportional to 103.84, 142.94 and 87.40 is: 120.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.84 : 142.94 = 87.40 : x
  2. Step 2: Convert to fraction form
    103.84/142.94 = 87.40/x
  3. Step 3: Cross multiply
    103.84x = 142.94 × 87.40
  4. Step 4: Simplify right side
    103.84x = 12,492.96
  5. Step 5: Solve for x
    x = 12,492.96/103.84
  6. Step 6: Final answer
    x = 120.31

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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.