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Finding the Fourth Proportional to 853.91, 1,280.87 and 421.10

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Solution

The fourth proportional to 853.91, 1,280.87 and 421.10 is: 631.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.91 : 1,280.87 = 421.10 : x
  2. Step 2: Convert to fraction form
    853.91/1,280.87 = 421.10/x
  3. Step 3: Cross multiply
    853.91x = 1,280.87 × 421.10
  4. Step 4: Simplify right side
    853.91x = 539,377.03
  5. Step 5: Solve for x
    x = 539,377.03/853.91
  6. Step 6: Final answer
    x = 631.65

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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.