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Finding the Fourth Proportional to 102.96, 142.14 and 78.51

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Solution

The fourth proportional to 102.96, 142.14 and 78.51 is: 108.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.96 : 142.14 = 78.51 : x
  2. Step 2: Convert to fraction form
    102.96/142.14 = 78.51/x
  3. Step 3: Cross multiply
    102.96x = 142.14 × 78.51
  4. Step 4: Simplify right side
    102.96x = 11,159.41
  5. Step 5: Solve for x
    x = 11,159.41/102.96
  6. Step 6: Final answer
    x = 108.39

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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.