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Finding the Fourth Proportional to 717.69, 990.21 and 422.90

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Solution

The fourth proportional to 717.69, 990.21 and 422.90 is: 583.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.69 : 990.21 = 422.90 : x
  2. Step 2: Convert to fraction form
    717.69/990.21 = 422.90/x
  3. Step 3: Cross multiply
    717.69x = 990.21 × 422.90
  4. Step 4: Simplify right side
    717.69x = 418,759.81
  5. Step 5: Solve for x
    x = 418,759.81/717.69
  6. Step 6: Final answer
    x = 583.48

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.