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Finding the Fourth Proportional to 790.64, 1,090.90 and 685.56

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Solution

The fourth proportional to 790.64, 1,090.90 and 685.56 is: 945.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    790.64 : 1,090.90 = 685.56 : x
  2. Step 2: Convert to fraction form
    790.64/1,090.90 = 685.56/x
  3. Step 3: Cross multiply
    790.64x = 1,090.90 × 685.56
  4. Step 4: Simplify right side
    790.64x = 747,877.40
  5. Step 5: Solve for x
    x = 747,877.40/790.64
  6. Step 6: Final answer
    x = 945.91

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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.