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Finding the Fourth Proportional to 969.87, 1,339.53 and 639.77

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Solution

The fourth proportional to 969.87, 1,339.53 and 639.77 is: 883.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    969.87 : 1,339.53 = 639.77 : x
  2. Step 2: Convert to fraction form
    969.87/1,339.53 = 639.77/x
  3. Step 3: Cross multiply
    969.87x = 1,339.53 × 639.77
  4. Step 4: Simplify right side
    969.87x = 856,984.41
  5. Step 5: Solve for x
    x = 856,984.41/969.87
  6. Step 6: Final answer
    x = 883.61

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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.