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Finding the Fourth Proportional to 1,390.60, 1,919 and 801.12

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Solution

The fourth proportional to 1,390.60, 1,919 and 801.12 is: 1,105.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.60 : 1,919 = 801.12 : x
  2. Step 2: Convert to fraction form
    1,390.60/1,919 = 801.12/x
  3. Step 3: Cross multiply
    1,390.60x = 1,919 × 801.12
  4. Step 4: Simplify right side
    1,390.60x = 1,537,349.28
  5. Step 5: Solve for x
    x = 1,537,349.28/1,390.60
  6. Step 6: Final answer
    x = 1,105.53

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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.