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Finding the Fourth Proportional to 857.66, 1,287.21 and 338.02

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Solution

The fourth proportional to 857.66, 1,287.21 and 338.02 is: 507.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.66 : 1,287.21 = 338.02 : x
  2. Step 2: Convert to fraction form
    857.66/1,287.21 = 338.02/x
  3. Step 3: Cross multiply
    857.66x = 1,287.21 × 338.02
  4. Step 4: Simplify right side
    857.66x = 435,099.51
  5. Step 5: Solve for x
    x = 435,099.51/857.66
  6. Step 6: Final answer
    x = 507.31

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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.