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Finding the Fourth Proportional to 1,249.51, 1,724.30 and 690

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Solution

The fourth proportional to 1,249.51, 1,724.30 and 690 is: 952.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,249.51 : 1,724.30 = 690 : x
  2. Step 2: Convert to fraction form
    1,249.51/1,724.30 = 690/x
  3. Step 3: Cross multiply
    1,249.51x = 1,724.30 × 690
  4. Step 4: Simplify right side
    1,249.51x = 1,189,768.73
  5. Step 5: Solve for x
    x = 1,189,768.73/1,249.51
  6. Step 6: Final answer
    x = 952.19

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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.