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Finding the Fourth Proportional to 1,209.70, 1,811.50 and 769.60

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Solution

The fourth proportional to 1,209.70, 1,811.50 and 769.60 is: 1,152.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.70 : 1,811.50 = 769.60 : x
  2. Step 2: Convert to fraction form
    1,209.70/1,811.50 = 769.60/x
  3. Step 3: Cross multiply
    1,209.70x = 1,811.50 × 769.60
  4. Step 4: Simplify right side
    1,209.70x = 1,394,130.40
  5. Step 5: Solve for x
    x = 1,394,130.40/1,209.70
  6. Step 6: Final answer
    x = 1,152.46

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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.