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Finding the Fourth Proportional to 817.12, 1,127.78 and 485.73

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Solution

The fourth proportional to 817.12, 1,127.78 and 485.73 is: 670.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.12 : 1,127.78 = 485.73 : x
  2. Step 2: Convert to fraction form
    817.12/1,127.78 = 485.73/x
  3. Step 3: Cross multiply
    817.12x = 1,127.78 × 485.73
  4. Step 4: Simplify right side
    817.12x = 547,796.58
  5. Step 5: Solve for x
    x = 547,796.58/817.12
  6. Step 6: Final answer
    x = 670.40

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.