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Finding the Fourth Proportional to 821.76, 1,231.80 and 456.72

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Solution

The fourth proportional to 821.76, 1,231.80 and 456.72 is: 684.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.76 : 1,231.80 = 456.72 : x
  2. Step 2: Convert to fraction form
    821.76/1,231.80 = 456.72/x
  3. Step 3: Cross multiply
    821.76x = 1,231.80 × 456.72
  4. Step 4: Simplify right side
    821.76x = 562,587.70
  5. Step 5: Solve for x
    x = 562,587.70/821.76
  6. Step 6: Final answer
    x = 684.61

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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.