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Finding the Fourth Proportional to 857.81, 1,287.41 and 487.84

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Solution

The fourth proportional to 857.81, 1,287.41 and 487.84 is: 732.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.81 : 1,287.41 = 487.84 : x
  2. Step 2: Convert to fraction form
    857.81/1,287.41 = 487.84/x
  3. Step 3: Cross multiply
    857.81x = 1,287.41 × 487.84
  4. Step 4: Simplify right side
    857.81x = 628,050.09
  5. Step 5: Solve for x
    x = 628,050.09/857.81
  6. Step 6: Final answer
    x = 732.16

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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.