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Finding the Fourth Proportional to 1,220.91, 1,684.87 and 778.71

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Solution

The fourth proportional to 1,220.91, 1,684.87 and 778.71 is: 1,074.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.91 : 1,684.87 = 778.71 : x
  2. Step 2: Convert to fraction form
    1,220.91/1,684.87 = 778.71/x
  3. Step 3: Cross multiply
    1,220.91x = 1,684.87 × 778.71
  4. Step 4: Simplify right side
    1,220.91x = 1,312,029.49
  5. Step 5: Solve for x
    x = 1,312,029.49/1,220.91
  6. Step 6: Final answer
    x = 1,074.64

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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.