Question:
ABC is an equilateral triangle and AD is the altitude on BC . If the coordinates of A are (1, 2) and that of D are (-2, 6) then what is the equation of BC?
ABC is an equilateral triangle and AD is the altitude on BC . If the coordinates of A are (1, 2) and that of D are (-2, 6) then what is the equation of BC?
Options:
- a) 3x + 4y – 18 = 0
- b) 4x + 3y – 1 = 0
- c) 4x – 3y = 26
- d) 3x – 4y + 30 = 0
- a) 3x + 4y – 18 = 0
- b) 4x + 3y – 1 = 0
- c) 4x – 3y = 26
- d) 3x – 4y + 30 = 0
correct answer : d)
Explanation:
Slope of AD = 62
21
–
—
=
4
3-
\ Slope of BC = 3
4
Equation of BC is
y – 6 = 3
4
(x + 2) Þ 3x – 4y + 30 = 0
Slope of AD = 62
21
–
—
=
4
3-
\ Slope of BC = 3
4
Equation of BC is
y – 6 = 3
4
(x + 2) Þ 3x – 4y + 30 = 0