Home / 1,211.20-1,671.36-687.12

Finding the Fourth Proportional to 1,211.20, 1,671.36 and 687.12

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Solution

The fourth proportional to 1,211.20, 1,671.36 and 687.12 is: 948.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,211.20 : 1,671.36 = 687.12 : x
  2. Step 2: Convert to fraction form
    1,211.20/1,671.36 = 687.12/x
  3. Step 3: Cross multiply
    1,211.20x = 1,671.36 × 687.12
  4. Step 4: Simplify right side
    1,211.20x = 1,148,424.88
  5. Step 5: Solve for x
    x = 1,148,424.88/1,211.20
  6. Step 6: Final answer
    x = 948.17

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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.