Home / 1,121.52-1,682.80-688.40

Finding the Fourth Proportional to 1,121.52, 1,682.80 and 688.40

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Solution

The fourth proportional to 1,121.52, 1,682.80 and 688.40 is: 1,032.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,121.52 : 1,682.80 = 688.40 : x
  2. Step 2: Convert to fraction form
    1,121.52/1,682.80 = 688.40/x
  3. Step 3: Cross multiply
    1,121.52x = 1,682.80 × 688.40
  4. Step 4: Simplify right side
    1,121.52x = 1,158,439.52
  5. Step 5: Solve for x
    x = 1,158,439.52/1,121.52
  6. Step 6: Final answer
    x = 1,032.92

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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.