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Finding the Fourth Proportional to 103.42, 142.71 and 56.79

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Solution

The fourth proportional to 103.42, 142.71 and 56.79 is: 78.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.42 : 142.71 = 56.79 : x
  2. Step 2: Convert to fraction form
    103.42/142.71 = 56.79/x
  3. Step 3: Cross multiply
    103.42x = 142.71 × 56.79
  4. Step 4: Simplify right side
    103.42x = 8,103.50
  5. Step 5: Solve for x
    x = 8,103.50/103.42
  6. Step 6: Final answer
    x = 78.36

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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.