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Finding the Fourth Proportional to 719.40, 1,079.21 and 257.05

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Solution

The fourth proportional to 719.40, 1,079.21 and 257.05 is: 385.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.40 : 1,079.21 = 257.05 : x
  2. Step 2: Convert to fraction form
    719.40/1,079.21 = 257.05/x
  3. Step 3: Cross multiply
    719.40x = 1,079.21 × 257.05
  4. Step 4: Simplify right side
    719.40x = 277,409.65
  5. Step 5: Solve for x
    x = 277,409.65/719.40
  6. Step 6: Final answer
    x = 385.62

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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.