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Finding the Fourth Proportional to 719.75, 1,078.99 and 280.69

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Solution

The fourth proportional to 719.75, 1,078.99 and 280.69 is: 420.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.75 : 1,078.99 = 280.69 : x
  2. Step 2: Convert to fraction form
    719.75/1,078.99 = 280.69/x
  3. Step 3: Cross multiply
    719.75x = 1,078.99 × 280.69
  4. Step 4: Simplify right side
    719.75x = 302,858.30
  5. Step 5: Solve for x
    x = 302,858.30/719.75
  6. Step 6: Final answer
    x = 420.78

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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.