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Finding the Fourth Proportional to 821.72, 1,133.84 and 490.20

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Solution

The fourth proportional to 821.72, 1,133.84 and 490.20 is: 676.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.72 : 1,133.84 = 490.20 : x
  2. Step 2: Convert to fraction form
    821.72/1,133.84 = 490.20/x
  3. Step 3: Cross multiply
    821.72x = 1,133.84 × 490.20
  4. Step 4: Simplify right side
    821.72x = 555,808.37
  5. Step 5: Solve for x
    x = 555,808.37/821.72
  6. Step 6: Final answer
    x = 676.40

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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.