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Finding the Fourth Proportional to 102.78, 141.93 and 78.30

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Solution

The fourth proportional to 102.78, 141.93 and 78.30 is: 108.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.78 : 141.93 = 78.30 : x
  2. Step 2: Convert to fraction form
    102.78/141.93 = 78.30/x
  3. Step 3: Cross multiply
    102.78x = 141.93 × 78.30
  4. Step 4: Simplify right side
    102.78x = 11,113.12
  5. Step 5: Solve for x
    x = 11,113.12/102.78
  6. Step 6: Final answer
    x = 108.13

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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.