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Finding the Fourth Proportional to 1,206.81, 1,810.21 and 720.81

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Solution

The fourth proportional to 1,206.81, 1,810.21 and 720.81 is: 1,081.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,206.81 : 1,810.21 = 720.81 : x
  2. Step 2: Convert to fraction form
    1,206.81/1,810.21 = 720.81/x
  3. Step 3: Cross multiply
    1,206.81x = 1,810.21 × 720.81
  4. Step 4: Simplify right side
    1,206.81x = 1,304,817.47
  5. Step 5: Solve for x
    x = 1,304,817.47/1,206.81
  6. Step 6: Final answer
    x = 1,081.21

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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.