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Finding the Fourth Proportional to 857.84, 1,280.18 and 765.57

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Solution

The fourth proportional to 857.84, 1,280.18 and 765.57 is: 1,142.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.84 : 1,280.18 = 765.57 : x
  2. Step 2: Convert to fraction form
    857.84/1,280.18 = 765.57/x
  3. Step 3: Cross multiply
    857.84x = 1,280.18 × 765.57
  4. Step 4: Simplify right side
    857.84x = 980,063.57
  5. Step 5: Solve for x
    x = 980,063.57/857.84
  6. Step 6: Final answer
    x = 1,142.48

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.