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Finding the Fourth Proportional to 719.91, 1,080.36 and 257.70

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Solution

The fourth proportional to 719.91, 1,080.36 and 257.70 is: 386.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.91 : 1,080.36 = 257.70 : x
  2. Step 2: Convert to fraction form
    719.91/1,080.36 = 257.70/x
  3. Step 3: Cross multiply
    719.91x = 1,080.36 × 257.70
  4. Step 4: Simplify right side
    719.91x = 278,408.77
  5. Step 5: Solve for x
    x = 278,408.77/719.91
  6. Step 6: Final answer
    x = 386.73

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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.