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Finding the Fourth Proportional to 621.15, 857.54 and 388.59

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Solution

The fourth proportional to 621.15, 857.54 and 388.59 is: 536.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.15 : 857.54 = 388.59 : x
  2. Step 2: Convert to fraction form
    621.15/857.54 = 388.59/x
  3. Step 3: Cross multiply
    621.15x = 857.54 × 388.59
  4. Step 4: Simplify right side
    621.15x = 333,229.53
  5. Step 5: Solve for x
    x = 333,229.53/621.15
  6. Step 6: Final answer
    x = 536.47

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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.