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Finding the Fourth Proportional to 720.31, 1,080.63 and 258.12

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Solution

The fourth proportional to 720.31, 1,080.63 and 258.12 is: 387.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.31 : 1,080.63 = 258.12 : x
  2. Step 2: Convert to fraction form
    720.31/1,080.63 = 258.12/x
  3. Step 3: Cross multiply
    720.31x = 1,080.63 × 258.12
  4. Step 4: Simplify right side
    720.31x = 278,932.22
  5. Step 5: Solve for x
    x = 278,932.22/720.31
  6. Step 6: Final answer
    x = 387.24

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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.