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Finding the Fourth Proportional to 1,187.41, 1,638.37 and 689.79

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Solution

The fourth proportional to 1,187.41, 1,638.37 and 689.79 is: 951.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.41 : 1,638.37 = 689.79 : x
  2. Step 2: Convert to fraction form
    1,187.41/1,638.37 = 689.79/x
  3. Step 3: Cross multiply
    1,187.41x = 1,638.37 × 689.79
  4. Step 4: Simplify right side
    1,187.41x = 1,130,129.52
  5. Step 5: Solve for x
    x = 1,130,129.52/1,187.41
  6. Step 6: Final answer
    x = 951.76

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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.