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Finding the Fourth Proportional to 1,318.90, 1,820.10 and 821.74

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Solution

The fourth proportional to 1,318.90, 1,820.10 and 821.74 is: 1,134.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,318.90 : 1,820.10 = 821.74 : x
  2. Step 2: Convert to fraction form
    1,318.90/1,820.10 = 821.74/x
  3. Step 3: Cross multiply
    1,318.90x = 1,820.10 × 821.74
  4. Step 4: Simplify right side
    1,318.90x = 1,495,648.97
  5. Step 5: Solve for x
    x = 1,495,648.97/1,318.90
  6. Step 6: Final answer
    x = 1,134.01

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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.