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Finding the Fourth Proportional to 1,240.12, 1,860.78 and 509.80

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Solution

The fourth proportional to 1,240.12, 1,860.78 and 509.80 is: 764.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,240.12 : 1,860.78 = 509.80 : x
  2. Step 2: Convert to fraction form
    1,240.12/1,860.78 = 509.80/x
  3. Step 3: Cross multiply
    1,240.12x = 1,860.78 × 509.80
  4. Step 4: Simplify right side
    1,240.12x = 948,625.64
  5. Step 5: Solve for x
    x = 948,625.64/1,240.12
  6. Step 6: Final answer
    x = 764.95

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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.