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Finding the Fourth Proportional to 853.74, 1,281.15 and 420.93

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Solution

The fourth proportional to 853.74, 1,281.15 and 420.93 is: 631.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.74 : 1,281.15 = 420.93 : x
  2. Step 2: Convert to fraction form
    853.74/1,281.15 = 420.93/x
  3. Step 3: Cross multiply
    853.74x = 1,281.15 × 420.93
  4. Step 4: Simplify right side
    853.74x = 539,274.47
  5. Step 5: Solve for x
    x = 539,274.47/853.74
  6. Step 6: Final answer
    x = 631.66

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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.