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Finding the Fourth Proportional to 821.39, 1,229.88 and 512.63

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Solution

The fourth proportional to 821.39, 1,229.88 and 512.63 is: 767.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.39 : 1,229.88 = 512.63 : x
  2. Step 2: Convert to fraction form
    821.39/1,229.88 = 512.63/x
  3. Step 3: Cross multiply
    821.39x = 1,229.88 × 512.63
  4. Step 4: Simplify right side
    821.39x = 630,476.46
  5. Step 5: Solve for x
    x = 630,476.46/821.39
  6. Step 6: Final answer
    x = 767.57

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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.