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Finding the Fourth Proportional to 974.32, 1,344.78 and 642.80

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Solution

The fourth proportional to 974.32, 1,344.78 and 642.80 is: 887.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    974.32 : 1,344.78 = 642.80 : x
  2. Step 2: Convert to fraction form
    974.32/1,344.78 = 642.80/x
  3. Step 3: Cross multiply
    974.32x = 1,344.78 × 642.80
  4. Step 4: Simplify right side
    974.32x = 864,424.58
  5. Step 5: Solve for x
    x = 864,424.58/974.32
  6. Step 6: Final answer
    x = 887.21

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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.