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Finding the Fourth Proportional to 1,222.68, 1,686.66 and 780.12

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Solution

The fourth proportional to 1,222.68, 1,686.66 and 780.12 is: 1,076.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,222.68 : 1,686.66 = 780.12 : x
  2. Step 2: Convert to fraction form
    1,222.68/1,686.66 = 780.12/x
  3. Step 3: Cross multiply
    1,222.68x = 1,686.66 × 780.12
  4. Step 4: Simplify right side
    1,222.68x = 1,315,797.20
  5. Step 5: Solve for x
    x = 1,315,797.20/1,222.68
  6. Step 6: Final answer
    x = 1,076.16

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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.