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Finding the Fourth Proportional to 860.56, 1,291.21 and 422.20

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Solution

The fourth proportional to 860.56, 1,291.21 and 422.20 is: 633.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.56 : 1,291.21 = 422.20 : x
  2. Step 2: Convert to fraction form
    860.56/1,291.21 = 422.20/x
  3. Step 3: Cross multiply
    860.56x = 1,291.21 × 422.20
  4. Step 4: Simplify right side
    860.56x = 545,148.86
  5. Step 5: Solve for x
    x = 545,148.86/860.56
  6. Step 6: Final answer
    x = 633.48

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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.