NDA 2025
- Exam
- NDA
- Year
- 2025
- Subject
- Mathematics
- Chapter
- Three Dimensional Geometry
NDA 2025 · Mathematics · Three Dimensional Geometry
A(1, 2, -1) , B(2, 5, -2) and C(4, 4, -3) are three vertices of a...
, and are three vertices of a rectangle. What is the area of the rectangle?
Options
- A square units
- B square units
- C square units
- D square units
Correct answer
C. square units
Step-by-step solution
The given vertices of the rectangle are , and .
The direction ratios of the side are .
The length of the side is BC(4-2, 4-5, -3-(-2)) = (2, -1, -1)BC.
Now, checking the dot product of vectors and :
Since the dot product is zero, is perpendicular to , which means , , and are consecutive vertices forming a right angle at .
The area of the rectangle is the product of its adjacent sides:
Answer:
The direction ratios of the side are .
The length of the side is BC(4-2, 4-5, -3-(-2)) = (2, -1, -1)BC.
Now, checking the dot product of vectors and :
Since the dot product is zero, is perpendicular to , which means , , and are consecutive vertices forming a right angle at .
The area of the rectangle is the product of its adjacent sides:
Answer: