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Finding the Fourth Proportional to 659.36, 989.38 and 428.19

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Solution

The fourth proportional to 659.36, 989.38 and 428.19 is: 642.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.36 : 989.38 = 428.19 : x
  2. Step 2: Convert to fraction form
    659.36/989.38 = 428.19/x
  3. Step 3: Cross multiply
    659.36x = 989.38 × 428.19
  4. Step 4: Simplify right side
    659.36x = 423,642.62
  5. Step 5: Solve for x
    x = 423,642.62/659.36
  6. Step 6: Final answer
    x = 642.51

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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.