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Finding the Fourth Proportional to 719.61, 1,079.31 and 257.70

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Solution

The fourth proportional to 719.61, 1,079.31 and 257.70 is: 386.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.61 : 1,079.31 = 257.70 : x
  2. Step 2: Convert to fraction form
    719.61/1,079.31 = 257.70/x
  3. Step 3: Cross multiply
    719.61x = 1,079.31 × 257.70
  4. Step 4: Simplify right side
    719.61x = 278,138.19
  5. Step 5: Solve for x
    x = 278,138.19/719.61
  6. Step 6: Final answer
    x = 386.51

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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.