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Finding the Fourth Proportional to 821.34, 1,229.58 and 785.70

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Solution

The fourth proportional to 821.34, 1,229.58 and 785.70 is: 1,176.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.34 : 1,229.58 = 785.70 : x
  2. Step 2: Convert to fraction form
    821.34/1,229.58 = 785.70/x
  3. Step 3: Cross multiply
    821.34x = 1,229.58 × 785.70
  4. Step 4: Simplify right side
    821.34x = 966,081.01
  5. Step 5: Solve for x
    x = 966,081.01/821.34
  6. Step 6: Final answer
    x = 1,176.23

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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.