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Finding the Fourth Proportional to 75.78, 113.72 and 45.38

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Solution

The fourth proportional to 75.78, 113.72 and 45.38 is: 68.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    75.78 : 113.72 = 45.38 : x
  2. Step 2: Convert to fraction form
    75.78/113.72 = 45.38/x
  3. Step 3: Cross multiply
    75.78x = 113.72 × 45.38
  4. Step 4: Simplify right side
    75.78x = 5,159.82
  5. Step 5: Solve for x
    x = 5,159.82/75.78
  6. Step 6: Final answer
    x = 68.09

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.