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Finding the Fourth Proportional to 974.78, 1,344.61 and 643.09

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Solution

The fourth proportional to 974.78, 1,344.61 and 643.09 is: 887.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    974.78 : 1,344.61 = 643.09 : x
  2. Step 2: Convert to fraction form
    974.78/1,344.61 = 643.09/x
  3. Step 3: Cross multiply
    974.78x = 1,344.61 × 643.09
  4. Step 4: Simplify right side
    974.78x = 864,705.24
  5. Step 5: Solve for x
    x = 864,705.24/974.78
  6. Step 6: Final answer
    x = 887.08

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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.