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Finding the Fourth Proportional to 621.53, 858.36 and 388.79

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Solution

The fourth proportional to 621.53, 858.36 and 388.79 is: 536.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.53 : 858.36 = 388.79 : x
  2. Step 2: Convert to fraction form
    621.53/858.36 = 388.79/x
  3. Step 3: Cross multiply
    621.53x = 858.36 × 388.79
  4. Step 4: Simplify right side
    621.53x = 333,717.49
  5. Step 5: Solve for x
    x = 333,717.49/621.53
  6. Step 6: Final answer
    x = 536.93

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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.