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Finding the Fourth Proportional to 1,987.81, 2,981.77 and 947.92

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Solution

The fourth proportional to 1,987.81, 2,981.77 and 947.92 is: 1,421.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,987.81 : 2,981.77 = 947.92 : x
  2. Step 2: Convert to fraction form
    1,987.81/2,981.77 = 947.92/x
  3. Step 3: Cross multiply
    1,987.81x = 2,981.77 × 947.92
  4. Step 4: Simplify right side
    1,987.81x = 2,826,479.42
  5. Step 5: Solve for x
    x = 2,826,479.42/1,987.81
  6. Step 6: Final answer
    x = 1,421.91

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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.