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Finding the Fourth Proportional to 1,380.26, 1,905 and 790.68

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Solution

The fourth proportional to 1,380.26, 1,905 and 790.68 is: 1,091.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.26 : 1,905 = 790.68 : x
  2. Step 2: Convert to fraction form
    1,380.26/1,905 = 790.68/x
  3. Step 3: Cross multiply
    1,380.26x = 1,905 × 790.68
  4. Step 4: Simplify right side
    1,380.26x = 1,506,245.40
  5. Step 5: Solve for x
    x = 1,506,245.40/1,380.26
  6. Step 6: Final answer
    x = 1,091.28

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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.