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Finding the Fourth Proportional to 820, 1,131.78 and 509.68

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Solution

The fourth proportional to 820, 1,131.78 and 509.68 is: 703.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    820 : 1,131.78 = 509.68 : x
  2. Step 2: Convert to fraction form
    820/1,131.78 = 509.68/x
  3. Step 3: Cross multiply
    820x = 1,131.78 × 509.68
  4. Step 4: Simplify right side
    820x = 576,845.63
  5. Step 5: Solve for x
    x = 576,845.63/820
  6. Step 6: Final answer
    x = 703.47

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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.