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Finding the Fourth Proportional to 869.97, 1,305.60 and 639.47

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Solution

The fourth proportional to 869.97, 1,305.60 and 639.47 is: 959.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.97 : 1,305.60 = 639.47 : x
  2. Step 2: Convert to fraction form
    869.97/1,305.60 = 639.47/x
  3. Step 3: Cross multiply
    869.97x = 1,305.60 × 639.47
  4. Step 4: Simplify right side
    869.97x = 834,885.50
  5. Step 5: Solve for x
    x = 834,885.50/869.97
  6. Step 6: Final answer
    x = 959.67

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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.