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Finding the Fourth Proportional to 854.64, 1,280.76 and 421.36

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Solution

The fourth proportional to 854.64, 1,280.76 and 421.36 is: 631.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    854.64 : 1,280.76 = 421.36 : x
  2. Step 2: Convert to fraction form
    854.64/1,280.76 = 421.36/x
  3. Step 3: Cross multiply
    854.64x = 1,280.76 × 421.36
  4. Step 4: Simplify right side
    854.64x = 539,661.03
  5. Step 5: Solve for x
    x = 539,661.03/854.64
  6. Step 6: Final answer
    x = 631.45

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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.