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Finding the Fourth Proportional to 719.72, 1,080 and 257.90

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Solution

The fourth proportional to 719.72, 1,080 and 257.90 is: 386.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.72 : 1,080 = 257.90 : x
  2. Step 2: Convert to fraction form
    719.72/1,080 = 257.90/x
  3. Step 3: Cross multiply
    719.72x = 1,080 × 257.90
  4. Step 4: Simplify right side
    719.72x = 278,526.60
  5. Step 5: Solve for x
    x = 278,526.60/719.72
  6. Step 6: Final answer
    x = 386.99

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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.