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Finding the Fourth Proportional to 1,221.52, 1,685.43 and 723.78

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Solution

The fourth proportional to 1,221.52, 1,685.43 and 723.78 is: 998.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.52 : 1,685.43 = 723.78 : x
  2. Step 2: Convert to fraction form
    1,221.52/1,685.43 = 723.78/x
  3. Step 3: Cross multiply
    1,221.52x = 1,685.43 × 723.78
  4. Step 4: Simplify right side
    1,221.52x = 1,219,880.53
  5. Step 5: Solve for x
    x = 1,219,880.53/1,221.52
  6. Step 6: Final answer
    x = 998.66

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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.