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Finding the Fourth Proportional to 720.89, 1,080.67 and 258.56

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Solution

The fourth proportional to 720.89, 1,080.67 and 258.56 is: 387.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.89 : 1,080.67 = 258.56 : x
  2. Step 2: Convert to fraction form
    720.89/1,080.67 = 258.56/x
  3. Step 3: Cross multiply
    720.89x = 1,080.67 × 258.56
  4. Step 4: Simplify right side
    720.89x = 279,418.04
  5. Step 5: Solve for x
    x = 279,418.04/720.89
  6. Step 6: Final answer
    x = 387.60

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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.