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Finding the Fourth Proportional to 857.55, 1,287.27 and 686.28

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Solution

The fourth proportional to 857.55, 1,287.27 and 686.28 is: 1,030.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.55 : 1,287.27 = 686.28 : x
  2. Step 2: Convert to fraction form
    857.55/1,287.27 = 686.28/x
  3. Step 3: Cross multiply
    857.55x = 1,287.27 × 686.28
  4. Step 4: Simplify right side
    857.55x = 883,427.66
  5. Step 5: Solve for x
    x = 883,427.66/857.55
  6. Step 6: Final answer
    x = 1,030.18

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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.