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Finding the Fourth Proportional to 920.25, 1,380.38 and 407.25

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Solution

The fourth proportional to 920.25, 1,380.38 and 407.25 is: 610.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.25 : 1,380.38 = 407.25 : x
  2. Step 2: Convert to fraction form
    920.25/1,380.38 = 407.25/x
  3. Step 3: Cross multiply
    920.25x = 1,380.38 × 407.25
  4. Step 4: Simplify right side
    920.25x = 562,157.72
  5. Step 5: Solve for x
    x = 562,157.72/920.25
  6. Step 6: Final answer
    x = 610.88

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Double scale
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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.