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Finding the Fourth Proportional to 828.10, 1,242.15 and 620.20

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Solution

The fourth proportional to 828.10, 1,242.15 and 620.20 is: 930.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.10 : 1,242.15 = 620.20 : x
  2. Step 2: Convert to fraction form
    828.10/1,242.15 = 620.20/x
  3. Step 3: Cross multiply
    828.10x = 1,242.15 × 620.20
  4. Step 4: Simplify right side
    828.10x = 770,381.43
  5. Step 5: Solve for x
    x = 770,381.43/828.10
  6. Step 6: Final answer
    x = 930.30

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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.