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Finding the Fourth Proportional to 857.57, 1,286.45 and 280.45

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Solution

The fourth proportional to 857.57, 1,286.45 and 280.45 is: 420.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.57 : 1,286.45 = 280.45 : x
  2. Step 2: Convert to fraction form
    857.57/1,286.45 = 280.45/x
  3. Step 3: Cross multiply
    857.57x = 1,286.45 × 280.45
  4. Step 4: Simplify right side
    857.57x = 360,777.07
  5. Step 5: Solve for x
    x = 360,777.07/857.57
  6. Step 6: Final answer
    x = 420.70

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1.5x scale

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.