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Finding the Fourth Proportional to 257.80, 386.61 and 120.91

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Solution

The fourth proportional to 257.80, 386.61 and 120.91 is: 181.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.80 : 386.61 = 120.91 : x
  2. Step 2: Convert to fraction form
    257.80/386.61 = 120.91/x
  3. Step 3: Cross multiply
    257.80x = 386.61 × 120.91
  4. Step 4: Simplify right side
    257.80x = 46,745.02
  5. Step 5: Solve for x
    x = 46,745.02/257.80
  6. Step 6: Final answer
    x = 181.32

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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.