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Finding the Fourth Proportional to 921.45, 1,271.34 and 641.37

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Solution

The fourth proportional to 921.45, 1,271.34 and 641.37 is: 884.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.45 : 1,271.34 = 641.37 : x
  2. Step 2: Convert to fraction form
    921.45/1,271.34 = 641.37/x
  3. Step 3: Cross multiply
    921.45x = 1,271.34 × 641.37
  4. Step 4: Simplify right side
    921.45x = 815,399.34
  5. Step 5: Solve for x
    x = 815,399.34/921.45
  6. Step 6: Final answer
    x = 884.91

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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.