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Finding the Fourth Proportional to 1,209.23, 1,812.79 and 721.25

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Solution

The fourth proportional to 1,209.23, 1,812.79 and 721.25 is: 1,081.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.23 : 1,812.79 = 721.25 : x
  2. Step 2: Convert to fraction form
    1,209.23/1,812.79 = 721.25/x
  3. Step 3: Cross multiply
    1,209.23x = 1,812.79 × 721.25
  4. Step 4: Simplify right side
    1,209.23x = 1,307,474.79
  5. Step 5: Solve for x
    x = 1,307,474.79/1,209.23
  6. Step 6: Final answer
    x = 1,081.25

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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.