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Finding the Fourth Proportional to 920.45, 1,269.96 and 640.37

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Solution

The fourth proportional to 920.45, 1,269.96 and 640.37 is: 883.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.45 : 1,269.96 = 640.37 : x
  2. Step 2: Convert to fraction form
    920.45/1,269.96 = 640.37/x
  3. Step 3: Cross multiply
    920.45x = 1,269.96 × 640.37
  4. Step 4: Simplify right side
    920.45x = 813,237.94
  5. Step 5: Solve for x
    x = 813,237.94/920.45
  6. Step 6: Final answer
    x = 883.53

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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.