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Finding the Fourth Proportional to 621.67, 931.46 and 438.76

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Solution

The fourth proportional to 621.67, 931.46 and 438.76 is: 657.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.67 : 931.46 = 438.76 : x
  2. Step 2: Convert to fraction form
    621.67/931.46 = 438.76/x
  3. Step 3: Cross multiply
    621.67x = 931.46 × 438.76
  4. Step 4: Simplify right side
    621.67x = 408,686.16
  5. Step 5: Solve for x
    x = 408,686.16/621.67
  6. Step 6: Final answer
    x = 657.40

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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.