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Finding the Fourth Proportional to 720.08, 1,079.76 and 257.79

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Solution

The fourth proportional to 720.08, 1,079.76 and 257.79 is: 386.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.08 : 1,079.76 = 257.79 : x
  2. Step 2: Convert to fraction form
    720.08/1,079.76 = 257.79/x
  3. Step 3: Cross multiply
    720.08x = 1,079.76 × 257.79
  4. Step 4: Simplify right side
    720.08x = 278,351.33
  5. Step 5: Solve for x
    x = 278,351.33/720.08
  6. Step 6: Final answer
    x = 386.56

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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.