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Finding the Fourth Proportional to 720.05, 1,080.09 and 257.87

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Solution

The fourth proportional to 720.05, 1,080.09 and 257.87 is: 386.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.05 : 1,080.09 = 257.87 : x
  2. Step 2: Convert to fraction form
    720.05/1,080.09 = 257.87/x
  3. Step 3: Cross multiply
    720.05x = 1,080.09 × 257.87
  4. Step 4: Simplify right side
    720.05x = 278,517.41
  5. Step 5: Solve for x
    x = 278,517.41/720.05
  6. Step 6: Final answer
    x = 386.81

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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.