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Finding the Fourth Proportional to 1,290.66, 1,780.50 and 818.22

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Solution

The fourth proportional to 1,290.66, 1,780.50 and 818.22 is: 1,128.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.66 : 1,780.50 = 818.22 : x
  2. Step 2: Convert to fraction form
    1,290.66/1,780.50 = 818.22/x
  3. Step 3: Cross multiply
    1,290.66x = 1,780.50 × 818.22
  4. Step 4: Simplify right side
    1,290.66x = 1,456,840.71
  5. Step 5: Solve for x
    x = 1,456,840.71/1,290.66
  6. Step 6: Final answer
    x = 1,128.76

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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.