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Finding the Fourth Proportional to 1,390, 1,918.37 and 800.53

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Solution

The fourth proportional to 1,390, 1,918.37 and 800.53 is: 1,104.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390 : 1,918.37 = 800.53 : x
  2. Step 2: Convert to fraction form
    1,390/1,918.37 = 800.53/x
  3. Step 3: Cross multiply
    1,390x = 1,918.37 × 800.53
  4. Step 4: Simplify right side
    1,390x = 1,535,712.74
  5. Step 5: Solve for x
    x = 1,535,712.74/1,390
  6. Step 6: Final answer
    x = 1,104.83

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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.