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Finding the Fourth Proportional to 853.99, 1,279.37 and 421.45

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Solution

The fourth proportional to 853.99, 1,279.37 and 421.45 is: 631.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.99 : 1,279.37 = 421.45 : x
  2. Step 2: Convert to fraction form
    853.99/1,279.37 = 421.45/x
  3. Step 3: Cross multiply
    853.99x = 1,279.37 × 421.45
  4. Step 4: Simplify right side
    853.99x = 539,188.38
  5. Step 5: Solve for x
    x = 539,188.38/853.99
  6. Step 6: Final answer
    x = 631.38

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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.