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Finding the Fourth Proportional to 681.51, 939.79 and 666.44

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Solution

The fourth proportional to 681.51, 939.79 and 666.44 is: 919.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.51 : 939.79 = 666.44 : x
  2. Step 2: Convert to fraction form
    681.51/939.79 = 666.44/x
  3. Step 3: Cross multiply
    681.51x = 939.79 × 666.44
  4. Step 4: Simplify right side
    681.51x = 626,313.65
  5. Step 5: Solve for x
    x = 626,313.65/681.51
  6. Step 6: Final answer
    x = 919.01

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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.