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Finding the Fourth Proportional to 811.81, 1,119.90 and 780.37

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Solution

The fourth proportional to 811.81, 1,119.90 and 780.37 is: 1,076.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.81 : 1,119.90 = 780.37 : x
  2. Step 2: Convert to fraction form
    811.81/1,119.90 = 780.37/x
  3. Step 3: Cross multiply
    811.81x = 1,119.90 × 780.37
  4. Step 4: Simplify right side
    811.81x = 873,936.36
  5. Step 5: Solve for x
    x = 873,936.36/811.81
  6. Step 6: Final answer
    x = 1,076.53

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.