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Finding the Fourth Proportional to 1,223.75, 1,688.78 and 664.22

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Solution

The fourth proportional to 1,223.75, 1,688.78 and 664.22 is: 916.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,223.75 : 1,688.78 = 664.22 : x
  2. Step 2: Convert to fraction form
    1,223.75/1,688.78 = 664.22/x
  3. Step 3: Cross multiply
    1,223.75x = 1,688.78 × 664.22
  4. Step 4: Simplify right side
    1,223.75x = 1,121,721.45
  5. Step 5: Solve for x
    x = 1,121,721.45/1,223.75
  6. Step 6: Final answer
    x = 916.63

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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.