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Finding the Fourth Proportional to 997.80, 1,377.20 and 661.75

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Solution

The fourth proportional to 997.80, 1,377.20 and 661.75 is: 913.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    997.80 : 1,377.20 = 661.75 : x
  2. Step 2: Convert to fraction form
    997.80/1,377.20 = 661.75/x
  3. Step 3: Cross multiply
    997.80x = 1,377.20 × 661.75
  4. Step 4: Simplify right side
    997.80x = 911,368.06
  5. Step 5: Solve for x
    x = 911,368.06/997.80
  6. Step 6: Final answer
    x = 913.38

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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.