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Finding the Fourth Proportional to 1,442.09, 1,990.11 and 821.09

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Solution

The fourth proportional to 1,442.09, 1,990.11 and 821.09 is: 1,133.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,442.09 : 1,990.11 = 821.09 : x
  2. Step 2: Convert to fraction form
    1,442.09/1,990.11 = 821.09/x
  3. Step 3: Cross multiply
    1,442.09x = 1,990.11 × 821.09
  4. Step 4: Simplify right side
    1,442.09x = 1,634,059.42
  5. Step 5: Solve for x
    x = 1,634,059.42/1,442.09
  6. Step 6: Final answer
    x = 1,133.12

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1.5x scale

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.