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Finding the Fourth Proportional to 1,390.42, 1,918.74 and 800.95

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Solution

The fourth proportional to 1,390.42, 1,918.74 and 800.95 is: 1,105.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.42 : 1,918.74 = 800.95 : x
  2. Step 2: Convert to fraction form
    1,390.42/1,918.74 = 800.95/x
  3. Step 3: Cross multiply
    1,390.42x = 1,918.74 × 800.95
  4. Step 4: Simplify right side
    1,390.42x = 1,536,814.80
  5. Step 5: Solve for x
    x = 1,536,814.80/1,390.42
  6. Step 6: Final answer
    x = 1,105.29

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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.