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Finding the Fourth Proportional to 980.39, 1,352.79 and 681.72

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Solution

The fourth proportional to 980.39, 1,352.79 and 681.72 is: 940.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.39 : 1,352.79 = 681.72 : x
  2. Step 2: Convert to fraction form
    980.39/1,352.79 = 681.72/x
  3. Step 3: Cross multiply
    980.39x = 1,352.79 × 681.72
  4. Step 4: Simplify right side
    980.39x = 922,224.00
  5. Step 5: Solve for x
    x = 922,224.00/980.39
  6. Step 6: Final answer
    x = 940.68

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Double scale
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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.