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Finding the Fourth Proportional to 1,221, 1,685.54 and 779.50

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Solution

The fourth proportional to 1,221, 1,685.54 and 779.50 is: 1,076.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221 : 1,685.54 = 779.50 : x
  2. Step 2: Convert to fraction form
    1,221/1,685.54 = 779.50/x
  3. Step 3: Cross multiply
    1,221x = 1,685.54 × 779.50
  4. Step 4: Simplify right side
    1,221x = 1,313,878.43
  5. Step 5: Solve for x
    x = 1,313,878.43/1,221
  6. Step 6: Final answer
    x = 1,076.07

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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.