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Finding the Fourth Proportional to 102.84, 142.14 and 78.36

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Solution

The fourth proportional to 102.84, 142.14 and 78.36 is: 108.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.84 : 142.14 = 78.36 : x
  2. Step 2: Convert to fraction form
    102.84/142.14 = 78.36/x
  3. Step 3: Cross multiply
    102.84x = 142.14 × 78.36
  4. Step 4: Simplify right side
    102.84x = 11,138.09
  5. Step 5: Solve for x
    x = 11,138.09/102.84
  6. Step 6: Final answer
    x = 108.31

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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.