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Finding the Fourth Proportional to 131.45, 196.77 and 85.70

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Solution

The fourth proportional to 131.45, 196.77 and 85.70 is: 128.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.45 : 196.77 = 85.70 : x
  2. Step 2: Convert to fraction form
    131.45/196.77 = 85.70/x
  3. Step 3: Cross multiply
    131.45x = 196.77 × 85.70
  4. Step 4: Simplify right side
    131.45x = 16,862.38
  5. Step 5: Solve for x
    x = 16,862.38/131.45
  6. Step 6: Final answer
    x = 128.28

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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.