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Finding the Fourth Proportional to 1,220.64, 1,684.07 and 689.45

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Solution

The fourth proportional to 1,220.64, 1,684.07 and 689.45 is: 951.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.64 : 1,684.07 = 689.45 : x
  2. Step 2: Convert to fraction form
    1,220.64/1,684.07 = 689.45/x
  3. Step 3: Cross multiply
    1,220.64x = 1,684.07 × 689.45
  4. Step 4: Simplify right side
    1,220.64x = 1,161,076.66
  5. Step 5: Solve for x
    x = 1,161,076.66/1,220.64
  6. Step 6: Final answer
    x = 951.21

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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.