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Finding the Fourth Proportional to 1,222.13, 1,685.73 and 780.59

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Solution

The fourth proportional to 1,222.13, 1,685.73 and 780.59 is: 1,076.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,222.13 : 1,685.73 = 780.59 : x
  2. Step 2: Convert to fraction form
    1,222.13/1,685.73 = 780.59/x
  3. Step 3: Cross multiply
    1,222.13x = 1,685.73 × 780.59
  4. Step 4: Simplify right side
    1,222.13x = 1,315,863.98
  5. Step 5: Solve for x
    x = 1,315,863.98/1,222.13
  6. Step 6: Final answer
    x = 1,076.70

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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.