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Finding the Fourth Proportional to 621.63, 857.85 and 389.07

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Solution

The fourth proportional to 621.63, 857.85 and 389.07 is: 536.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.63 : 857.85 = 389.07 : x
  2. Step 2: Convert to fraction form
    621.63/857.85 = 389.07/x
  3. Step 3: Cross multiply
    621.63x = 857.85 × 389.07
  4. Step 4: Simplify right side
    621.63x = 333,763.70
  5. Step 5: Solve for x
    x = 333,763.70/621.63
  6. Step 6: Final answer
    x = 536.92

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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.