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Finding the Fourth Proportional to 720.32, 1,080.88 and 391.25

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Solution

The fourth proportional to 720.32, 1,080.88 and 391.25 is: 587.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.32 : 1,080.88 = 391.25 : x
  2. Step 2: Convert to fraction form
    720.32/1,080.88 = 391.25/x
  3. Step 3: Cross multiply
    720.32x = 1,080.88 × 391.25
  4. Step 4: Simplify right side
    720.32x = 422,896.02
  5. Step 5: Solve for x
    x = 422,896.02/720.32
  6. Step 6: Final answer
    x = 587.10

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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.