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Finding the Fourth Proportional to 719.72, 1,079.65 and 257.55

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Solution

The fourth proportional to 719.72, 1,079.65 and 257.55 is: 386.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.72 : 1,079.65 = 257.55 : x
  2. Step 2: Convert to fraction form
    719.72/1,079.65 = 257.55/x
  3. Step 3: Cross multiply
    719.72x = 1,079.65 × 257.55
  4. Step 4: Simplify right side
    719.72x = 278,063.86
  5. Step 5: Solve for x
    x = 278,063.86/719.72
  6. Step 6: Final answer
    x = 386.35

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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.