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Finding the Fourth Proportional to 720.98, 1,081.31 and 258.79

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Solution

The fourth proportional to 720.98, 1,081.31 and 258.79 is: 388.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.98 : 1,081.31 = 258.79 : x
  2. Step 2: Convert to fraction form
    720.98/1,081.31 = 258.79/x
  3. Step 3: Cross multiply
    720.98x = 1,081.31 × 258.79
  4. Step 4: Simplify right side
    720.98x = 279,832.21
  5. Step 5: Solve for x
    x = 279,832.21/720.98
  6. Step 6: Final answer
    x = 388.13

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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.