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Finding the Fourth Proportional to 1,209.15, 1,812.81 and 661.80

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Solution

The fourth proportional to 1,209.15, 1,812.81 and 661.80 is: 992.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.15 : 1,812.81 = 661.80 : x
  2. Step 2: Convert to fraction form
    1,209.15/1,812.81 = 661.80/x
  3. Step 3: Cross multiply
    1,209.15x = 1,812.81 × 661.80
  4. Step 4: Simplify right side
    1,209.15x = 1,199,717.66
  5. Step 5: Solve for x
    x = 1,199,717.66/1,209.15
  6. Step 6: Final answer
    x = 992.20

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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.