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Finding the Fourth Proportional to 921.05, 1,271.62 and 641.18

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Solution

The fourth proportional to 921.05, 1,271.62 and 641.18 is: 885.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.05 : 1,271.62 = 641.18 : x
  2. Step 2: Convert to fraction form
    921.05/1,271.62 = 641.18/x
  3. Step 3: Cross multiply
    921.05x = 1,271.62 × 641.18
  4. Step 4: Simplify right side
    921.05x = 815,336.51
  5. Step 5: Solve for x
    x = 815,336.51/921.05
  6. Step 6: Final answer
    x = 885.23

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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.