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Finding the Fourth Proportional to 1,219.81, 1,683.39 and 688.90

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Solution

The fourth proportional to 1,219.81, 1,683.39 and 688.90 is: 950.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,219.81 : 1,683.39 = 688.90 : x
  2. Step 2: Convert to fraction form
    1,219.81/1,683.39 = 688.90/x
  3. Step 3: Cross multiply
    1,219.81x = 1,683.39 × 688.90
  4. Step 4: Simplify right side
    1,219.81x = 1,159,687.37
  5. Step 5: Solve for x
    x = 1,159,687.37/1,219.81
  6. Step 6: Final answer
    x = 950.71

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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.