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Finding the Fourth Proportional to 621.67, 858.05 and 388.75

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Solution

The fourth proportional to 621.67, 858.05 and 388.75 is: 536.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.67 : 858.05 = 388.75 : x
  2. Step 2: Convert to fraction form
    621.67/858.05 = 388.75/x
  3. Step 3: Cross multiply
    621.67x = 858.05 × 388.75
  4. Step 4: Simplify right side
    621.67x = 333,566.94
  5. Step 5: Solve for x
    x = 333,566.94/621.67
  6. Step 6: Final answer
    x = 536.57

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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.