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Finding the Fourth Proportional to 1,079.12, 1,489.28 and 686.48

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Solution

The fourth proportional to 1,079.12, 1,489.28 and 686.48 is: 947.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.12 : 1,489.28 = 686.48 : x
  2. Step 2: Convert to fraction form
    1,079.12/1,489.28 = 686.48/x
  3. Step 3: Cross multiply
    1,079.12x = 1,489.28 × 686.48
  4. Step 4: Simplify right side
    1,079.12x = 1,022,360.93
  5. Step 5: Solve for x
    x = 1,022,360.93/1,079.12
  6. Step 6: Final answer
    x = 947.40

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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.