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Finding the Fourth Proportional to 840.68, 1,261.20 and 320.84

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Solution

The fourth proportional to 840.68, 1,261.20 and 320.84 is: 481.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.68 : 1,261.20 = 320.84 : x
  2. Step 2: Convert to fraction form
    840.68/1,261.20 = 320.84/x
  3. Step 3: Cross multiply
    840.68x = 1,261.20 × 320.84
  4. Step 4: Simplify right side
    840.68x = 404,643.41
  5. Step 5: Solve for x
    x = 404,643.41/840.68
  6. Step 6: Final answer
    x = 481.33

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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.