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Finding the Fourth Proportional to 30.78, 42.43 and 26.42

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Solution

The fourth proportional to 30.78, 42.43 and 26.42 is: 36.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.78 : 42.43 = 26.42 : x
  2. Step 2: Convert to fraction form
    30.78/42.43 = 26.42/x
  3. Step 3: Cross multiply
    30.78x = 42.43 × 26.42
  4. Step 4: Simplify right side
    30.78x = 1,121.00
  5. Step 5: Solve for x
    x = 1,121.00/30.78
  6. Step 6: Final answer
    x = 36.42

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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.