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Finding the Fourth Proportional to 1,212.74, 1,818.65 and 390.79

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Solution

The fourth proportional to 1,212.74, 1,818.65 and 390.79 is: 586.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.74 : 1,818.65 = 390.79 : x
  2. Step 2: Convert to fraction form
    1,212.74/1,818.65 = 390.79/x
  3. Step 3: Cross multiply
    1,212.74x = 1,818.65 × 390.79
  4. Step 4: Simplify right side
    1,212.74x = 710,713.48
  5. Step 5: Solve for x
    x = 710,713.48/1,212.74
  6. Step 6: Final answer
    x = 586.04

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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.