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Finding the Fourth Proportional to 825.80, 1,239.90 and 621.80

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Solution

The fourth proportional to 825.80, 1,239.90 and 621.80 is: 933.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    825.80 : 1,239.90 = 621.80 : x
  2. Step 2: Convert to fraction form
    825.80/1,239.90 = 621.80/x
  3. Step 3: Cross multiply
    825.80x = 1,239.90 × 621.80
  4. Step 4: Simplify right side
    825.80x = 770,969.82
  5. Step 5: Solve for x
    x = 770,969.82/825.80
  6. Step 6: Final answer
    x = 933.60

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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.