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Finding the Fourth Proportional to 821.66, 1,230.51 and 513.12

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Solution

The fourth proportional to 821.66, 1,230.51 and 513.12 is: 768.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.66 : 1,230.51 = 513.12 : x
  2. Step 2: Convert to fraction form
    821.66/1,230.51 = 513.12/x
  3. Step 3: Cross multiply
    821.66x = 1,230.51 × 513.12
  4. Step 4: Simplify right side
    821.66x = 631,399.29
  5. Step 5: Solve for x
    x = 631,399.29/821.66
  6. Step 6: Final answer
    x = 768.45

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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.