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Finding the Fourth Proportional to 257.70, 386.69 and 120.81

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Solution

The fourth proportional to 257.70, 386.69 and 120.81 is: 181.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.70 : 386.69 = 120.81 : x
  2. Step 2: Convert to fraction form
    257.70/386.69 = 120.81/x
  3. Step 3: Cross multiply
    257.70x = 386.69 × 120.81
  4. Step 4: Simplify right side
    257.70x = 46,716.02
  5. Step 5: Solve for x
    x = 46,716.02/257.70
  6. Step 6: Final answer
    x = 181.28

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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.