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Finding the Fourth Proportional to 1,281.34, 1,768.05 and 721.71

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Solution

The fourth proportional to 1,281.34, 1,768.05 and 721.71 is: 995.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.34 : 1,768.05 = 721.71 : x
  2. Step 2: Convert to fraction form
    1,281.34/1,768.05 = 721.71/x
  3. Step 3: Cross multiply
    1,281.34x = 1,768.05 × 721.71
  4. Step 4: Simplify right side
    1,281.34x = 1,276,021.40
  5. Step 5: Solve for x
    x = 1,276,021.40/1,281.34
  6. Step 6: Final answer
    x = 995.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.