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Finding the Fourth Proportional to 1,289.21, 1,778.57 and 791.00

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Solution

The fourth proportional to 1,289.21, 1,778.57 and 791.00 is: 1,091.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.21 : 1,778.57 = 791.00 : x
  2. Step 2: Convert to fraction form
    1,289.21/1,778.57 = 791.00/x
  3. Step 3: Cross multiply
    1,289.21x = 1,778.57 × 791.00
  4. Step 4: Simplify right side
    1,289.21x = 1,406,839.98
  5. Step 5: Solve for x
    x = 1,406,839.98/1,289.21
  6. Step 6: Final answer
    x = 1,091.24

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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.