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Finding the Fourth Proportional to 621.20, 931.78 and 255.90

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Solution

The fourth proportional to 621.20, 931.78 and 255.90 is: 383.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.20 : 931.78 = 255.90 : x
  2. Step 2: Convert to fraction form
    621.20/931.78 = 255.90/x
  3. Step 3: Cross multiply
    621.20x = 931.78 × 255.90
  4. Step 4: Simplify right side
    621.20x = 238,442.50
  5. Step 5: Solve for x
    x = 238,442.50/621.20
  6. Step 6: Final answer
    x = 383.84

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Double scale
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Similar ratio
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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.