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Finding the Fourth Proportional to 899.64, 1,243.62 and 639.90

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Solution

The fourth proportional to 899.64, 1,243.62 and 639.90 is: 884.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    899.64 : 1,243.62 = 639.90 : x
  2. Step 2: Convert to fraction form
    899.64/1,243.62 = 639.90/x
  3. Step 3: Cross multiply
    899.64x = 1,243.62 × 639.90
  4. Step 4: Simplify right side
    899.64x = 795,792.44
  5. Step 5: Solve for x
    x = 795,792.44/899.64
  6. Step 6: Final answer
    x = 884.57

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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.