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Finding the Fourth Proportional to 629.40, 868.20 and 505.20

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Solution

The fourth proportional to 629.40, 868.20 and 505.20 is: 696.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    629.40 : 868.20 = 505.20 : x
  2. Step 2: Convert to fraction form
    629.40/868.20 = 505.20/x
  3. Step 3: Cross multiply
    629.40x = 868.20 × 505.20
  4. Step 4: Simplify right side
    629.40x = 438,614.64
  5. Step 5: Solve for x
    x = 438,614.64/629.40
  6. Step 6: Final answer
    x = 696.88

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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.