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Finding the Fourth Proportional to 1,221.26, 1,685.88 and 779.75

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Solution

The fourth proportional to 1,221.26, 1,685.88 and 779.75 is: 1,076.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.26 : 1,685.88 = 779.75 : x
  2. Step 2: Convert to fraction form
    1,221.26/1,685.88 = 779.75/x
  3. Step 3: Cross multiply
    1,221.26x = 1,685.88 × 779.75
  4. Step 4: Simplify right side
    1,221.26x = 1,314,556.50
  5. Step 5: Solve for x
    x = 1,314,556.50/1,221.26
  6. Step 6: Final answer
    x = 1,076.40

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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.