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Finding the Fourth Proportional to 92.70, 138.82 and 79.78

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Solution

The fourth proportional to 92.70, 138.82 and 79.78 is: 119.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.70 : 138.82 = 79.78 : x
  2. Step 2: Convert to fraction form
    92.70/138.82 = 79.78/x
  3. Step 3: Cross multiply
    92.70x = 138.82 × 79.78
  4. Step 4: Simplify right side
    92.70x = 11,075.06
  5. Step 5: Solve for x
    x = 11,075.06/92.70
  6. Step 6: Final answer
    x = 119.47

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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.