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Finding the Fourth Proportional to 1,281.79, 1,923.62 and 820.70

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Solution

The fourth proportional to 1,281.79, 1,923.62 and 820.70 is: 1,231.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.79 : 1,923.62 = 820.70 : x
  2. Step 2: Convert to fraction form
    1,281.79/1,923.62 = 820.70/x
  3. Step 3: Cross multiply
    1,281.79x = 1,923.62 × 820.70
  4. Step 4: Simplify right side
    1,281.79x = 1,578,701.21
  5. Step 5: Solve for x
    x = 1,578,701.21/1,281.79
  6. Step 6: Final answer
    x = 1,231.64

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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.