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Finding the Fourth Proportional to 620.81, 931.31 and 209.84

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Solution

The fourth proportional to 620.81, 931.31 and 209.84 is: 314.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.81 : 931.31 = 209.84 : x
  2. Step 2: Convert to fraction form
    620.81/931.31 = 209.84/x
  3. Step 3: Cross multiply
    620.81x = 931.31 × 209.84
  4. Step 4: Simplify right side
    620.81x = 195,420.38
  5. Step 5: Solve for x
    x = 195,420.38/620.81
  6. Step 6: Final answer
    x = 314.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.