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Finding the Fourth Proportional to 874.38, 1,207.42 and 639.66

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Solution

The fourth proportional to 874.38, 1,207.42 and 639.66 is: 883.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    874.38 : 1,207.42 = 639.66 : x
  2. Step 2: Convert to fraction form
    874.38/1,207.42 = 639.66/x
  3. Step 3: Cross multiply
    874.38x = 1,207.42 × 639.66
  4. Step 4: Simplify right side
    874.38x = 772,338.28
  5. Step 5: Solve for x
    x = 772,338.28/874.38
  6. Step 6: Final answer
    x = 883.30

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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.