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Finding the Fourth Proportional to 1,987.13, 2,980.62 and 816.81

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Solution

The fourth proportional to 1,987.13, 2,980.62 and 816.81 is: 1,225.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,987.13 : 2,980.62 = 816.81 : x
  2. Step 2: Convert to fraction form
    1,987.13/2,980.62 = 816.81/x
  3. Step 3: Cross multiply
    1,987.13x = 2,980.62 × 816.81
  4. Step 4: Simplify right side
    1,987.13x = 2,434,599.73
  5. Step 5: Solve for x
    x = 2,434,599.73/1,987.13
  6. Step 6: Final answer
    x = 1,225.18

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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.