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Finding the Fourth Proportional to 681.44, 1,016.80 and 640.16

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Solution

The fourth proportional to 681.44, 1,016.80 and 640.16 is: 955.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.44 : 1,016.80 = 640.16 : x
  2. Step 2: Convert to fraction form
    681.44/1,016.80 = 640.16/x
  3. Step 3: Cross multiply
    681.44x = 1,016.80 × 640.16
  4. Step 4: Simplify right side
    681.44x = 650,914.69
  5. Step 5: Solve for x
    x = 650,914.69/681.44
  6. Step 6: Final answer
    x = 955.20

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.