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Finding the Fourth Proportional to 813.98, 1,220.27 and 691.40

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Solution

The fourth proportional to 813.98, 1,220.27 and 691.40 is: 1,036.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.98 : 1,220.27 = 691.40 : x
  2. Step 2: Convert to fraction form
    813.98/1,220.27 = 691.40/x
  3. Step 3: Cross multiply
    813.98x = 1,220.27 × 691.40
  4. Step 4: Simplify right side
    813.98x = 843,685.12
  5. Step 5: Solve for x
    x = 843,685.12/813.98
  6. Step 6: Final answer
    x = 1,036.50

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.