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Finding the Fourth Proportional to 1,261.76, 1,740.72 and 820

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Solution

The fourth proportional to 1,261.76, 1,740.72 and 820 is: 1,131.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,261.76 : 1,740.72 = 820 : x
  2. Step 2: Convert to fraction form
    1,261.76/1,740.72 = 820/x
  3. Step 3: Cross multiply
    1,261.76x = 1,740.72 × 820
  4. Step 4: Simplify right side
    1,261.76x = 1,427,390.40
  5. Step 5: Solve for x
    x = 1,427,390.40/1,261.76
  6. Step 6: Final answer
    x = 1,131.27

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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.