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Finding the Fourth Proportional to 681.63, 1,021.81 and 621.51

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Solution

The fourth proportional to 681.63, 1,021.81 and 621.51 is: 931.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.63 : 1,021.81 = 621.51 : x
  2. Step 2: Convert to fraction form
    681.63/1,021.81 = 621.51/x
  3. Step 3: Cross multiply
    681.63x = 1,021.81 × 621.51
  4. Step 4: Simplify right side
    681.63x = 635,065.13
  5. Step 5: Solve for x
    x = 635,065.13/681.63
  6. Step 6: Final answer
    x = 931.69

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.