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Finding the Fourth Proportional to 1,209.70, 1,813.65 and 515.80

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Solution

The fourth proportional to 1,209.70, 1,813.65 and 515.80 is: 773.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.70 : 1,813.65 = 515.80 : x
  2. Step 2: Convert to fraction form
    1,209.70/1,813.65 = 515.80/x
  3. Step 3: Cross multiply
    1,209.70x = 1,813.65 × 515.80
  4. Step 4: Simplify right side
    1,209.70x = 935,480.67
  5. Step 5: Solve for x
    x = 935,480.67/1,209.70
  6. Step 6: Final answer
    x = 773.32

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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.