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Finding the Fourth Proportional to 1,219.40, 1,681.98 and 722

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Solution

The fourth proportional to 1,219.40, 1,681.98 and 722 is: 995.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,219.40 : 1,681.98 = 722 : x
  2. Step 2: Convert to fraction form
    1,219.40/1,681.98 = 722/x
  3. Step 3: Cross multiply
    1,219.40x = 1,681.98 × 722
  4. Step 4: Simplify right side
    1,219.40x = 1,214,389.56
  5. Step 5: Solve for x
    x = 1,214,389.56/1,219.40
  6. Step 6: Final answer
    x = 995.89

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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.