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Finding the Fourth Proportional to 1,321, 1,981.26 and 858.46

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Solution

The fourth proportional to 1,321, 1,981.26 and 858.46 is: 1,287.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321 : 1,981.26 = 858.46 : x
  2. Step 2: Convert to fraction form
    1,321/1,981.26 = 858.46/x
  3. Step 3: Cross multiply
    1,321x = 1,981.26 × 858.46
  4. Step 4: Simplify right side
    1,321x = 1,700,832.46
  5. Step 5: Solve for x
    x = 1,700,832.46/1,321
  6. Step 6: Final answer
    x = 1,287.53

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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.