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Finding the Fourth Proportional to 828.72, 1,242.81 and 280.80

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Solution

The fourth proportional to 828.72, 1,242.81 and 280.80 is: 421.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.72 : 1,242.81 = 280.80 : x
  2. Step 2: Convert to fraction form
    828.72/1,242.81 = 280.80/x
  3. Step 3: Cross multiply
    828.72x = 1,242.81 × 280.80
  4. Step 4: Simplify right side
    828.72x = 348,981.05
  5. Step 5: Solve for x
    x = 348,981.05/828.72
  6. Step 6: Final answer
    x = 421.11

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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.