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Finding the Fourth Proportional to 131.10, 196.78 and 77

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Solution

The fourth proportional to 131.10, 196.78 and 77 is: 115.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.10 : 196.78 = 77 : x
  2. Step 2: Convert to fraction form
    131.10/196.78 = 77/x
  3. Step 3: Cross multiply
    131.10x = 196.78 × 77
  4. Step 4: Simplify right side
    131.10x = 15,152.06
  5. Step 5: Solve for x
    x = 15,152.06/131.10
  6. Step 6: Final answer
    x = 115.58

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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.