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Finding the Fourth Proportional to 969.84, 1,339.92 and 639.36

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Solution

The fourth proportional to 969.84, 1,339.92 and 639.36 is: 883.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    969.84 : 1,339.92 = 639.36 : x
  2. Step 2: Convert to fraction form
    969.84/1,339.92 = 639.36/x
  3. Step 3: Cross multiply
    969.84x = 1,339.92 × 639.36
  4. Step 4: Simplify right side
    969.84x = 856,691.25
  5. Step 5: Solve for x
    x = 856,691.25/969.84
  6. Step 6: Final answer
    x = 883.33

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1.5x scale

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.