Home / 1,222.20-1,687.14-780.12

Finding the Fourth Proportional to 1,222.20, 1,687.14 and 780.12

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Solution

The fourth proportional to 1,222.20, 1,687.14 and 780.12 is: 1,076.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,222.20 : 1,687.14 = 780.12 : x
  2. Step 2: Convert to fraction form
    1,222.20/1,687.14 = 780.12/x
  3. Step 3: Cross multiply
    1,222.20x = 1,687.14 × 780.12
  4. Step 4: Simplify right side
    1,222.20x = 1,316,171.66
  5. Step 5: Solve for x
    x = 1,316,171.66/1,222.20
  6. Step 6: Final answer
    x = 1,076.89

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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.