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Finding the Fourth Proportional to 828.39, 1,242.15 and 389.28

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Solution

The fourth proportional to 828.39, 1,242.15 and 389.28 is: 583.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.39 : 1,242.15 = 389.28 : x
  2. Step 2: Convert to fraction form
    828.39/1,242.15 = 389.28/x
  3. Step 3: Cross multiply
    828.39x = 1,242.15 × 389.28
  4. Step 4: Simplify right side
    828.39x = 483,544.15
  5. Step 5: Solve for x
    x = 483,544.15/828.39
  6. Step 6: Final answer
    x = 583.72

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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.