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Finding the Fourth Proportional to 875.72, 1,310.88 and 721.28

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Solution

The fourth proportional to 875.72, 1,310.88 and 721.28 is: 1,079.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    875.72 : 1,310.88 = 721.28 : x
  2. Step 2: Convert to fraction form
    875.72/1,310.88 = 721.28/x
  3. Step 3: Cross multiply
    875.72x = 1,310.88 × 721.28
  4. Step 4: Simplify right side
    875.72x = 945,511.53
  5. Step 5: Solve for x
    x = 945,511.53/875.72
  6. Step 6: Final answer
    x = 1,079.70

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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.