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Finding the Fourth Proportional to 679.40, 938.28 and 447.20

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Solution

The fourth proportional to 679.40, 938.28 and 447.20 is: 617.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.40 : 938.28 = 447.20 : x
  2. Step 2: Convert to fraction form
    679.40/938.28 = 447.20/x
  3. Step 3: Cross multiply
    679.40x = 938.28 × 447.20
  4. Step 4: Simplify right side
    679.40x = 419,598.82
  5. Step 5: Solve for x
    x = 419,598.82/679.40
  6. Step 6: Final answer
    x = 617.60

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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.