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Finding the Fourth Proportional to 621.91, 931.35 and 438.45

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Solution

The fourth proportional to 621.91, 931.35 and 438.45 is: 656.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.91 : 931.35 = 438.45 : x
  2. Step 2: Convert to fraction form
    621.91/931.35 = 438.45/x
  3. Step 3: Cross multiply
    621.91x = 931.35 × 438.45
  4. Step 4: Simplify right side
    621.91x = 408,346.09
  5. Step 5: Solve for x
    x = 408,346.09/621.91
  6. Step 6: Final answer
    x = 656.60

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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.