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Finding the Fourth Proportional to 131.21, 181.20 and 103.78

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Solution

The fourth proportional to 131.21, 181.20 and 103.78 is: 143.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.21 : 181.20 = 103.78 : x
  2. Step 2: Convert to fraction form
    131.21/181.20 = 103.78/x
  3. Step 3: Cross multiply
    131.21x = 181.20 × 103.78
  4. Step 4: Simplify right side
    131.21x = 18,804.87
  5. Step 5: Solve for x
    x = 18,804.87/131.21
  6. Step 6: Final answer
    x = 143.32

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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.