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Finding the Fourth Proportional to 828.71, 1,242.95 and 212.40

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Solution

The fourth proportional to 828.71, 1,242.95 and 212.40 is: 318.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.71 : 1,242.95 = 212.40 : x
  2. Step 2: Convert to fraction form
    828.71/1,242.95 = 212.40/x
  3. Step 3: Cross multiply
    828.71x = 1,242.95 × 212.40
  4. Step 4: Simplify right side
    828.71x = 263,998.02
  5. Step 5: Solve for x
    x = 263,998.02/828.71
  6. Step 6: Final answer
    x = 318.57

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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.