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Finding the Fourth Proportional to 899.40, 1,239.39 and 689.81

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Solution

The fourth proportional to 899.40, 1,239.39 and 689.81 is: 950.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    899.40 : 1,239.39 = 689.81 : x
  2. Step 2: Convert to fraction form
    899.40/1,239.39 = 689.81/x
  3. Step 3: Cross multiply
    899.40x = 1,239.39 × 689.81
  4. Step 4: Simplify right side
    899.40x = 854,937.42
  5. Step 5: Solve for x
    x = 854,937.42/899.40
  6. Step 6: Final answer
    x = 950.56

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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.