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Finding the Fourth Proportional to 1,220.31, 1,683.90 and 689.02

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Solution

The fourth proportional to 1,220.31, 1,683.90 and 689.02 is: 950.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.31 : 1,683.90 = 689.02 : x
  2. Step 2: Convert to fraction form
    1,220.31/1,683.90 = 689.02/x
  3. Step 3: Cross multiply
    1,220.31x = 1,683.90 × 689.02
  4. Step 4: Simplify right side
    1,220.31x = 1,160,236.57
  5. Step 5: Solve for x
    x = 1,160,236.57/1,220.31
  6. Step 6: Final answer
    x = 950.77

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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.