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Finding the Fourth Proportional to 742.80, 1,116.60 and 685.20

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Solution

The fourth proportional to 742.80, 1,116.60 and 685.20 is: 1,030.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    742.80 : 1,116.60 = 685.20 : x
  2. Step 2: Convert to fraction form
    742.80/1,116.60 = 685.20/x
  3. Step 3: Cross multiply
    742.80x = 1,116.60 × 685.20
  4. Step 4: Simplify right side
    742.80x = 765,094.32
  5. Step 5: Solve for x
    x = 765,094.32/742.80
  6. Step 6: Final answer
    x = 1,030.01

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.