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Finding the Fourth Proportional to 1,211.51, 1,817.28 and 389.79

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Solution

The fourth proportional to 1,211.51, 1,817.28 and 389.79 is: 584.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,211.51 : 1,817.28 = 389.79 : x
  2. Step 2: Convert to fraction form
    1,211.51/1,817.28 = 389.79/x
  3. Step 3: Cross multiply
    1,211.51x = 1,817.28 × 389.79
  4. Step 4: Simplify right side
    1,211.51x = 708,357.57
  5. Step 5: Solve for x
    x = 708,357.57/1,211.51
  6. Step 6: Final answer
    x = 584.69

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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.