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Finding the Fourth Proportional to 621.69, 858.21 and 400.75

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Solution

The fourth proportional to 621.69, 858.21 and 400.75 is: 553.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.69 : 858.21 = 400.75 : x
  2. Step 2: Convert to fraction form
    621.69/858.21 = 400.75/x
  3. Step 3: Cross multiply
    621.69x = 858.21 × 400.75
  4. Step 4: Simplify right side
    621.69x = 343,926.26
  5. Step 5: Solve for x
    x = 343,926.26/621.69
  6. Step 6: Final answer
    x = 553.21

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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.