Question

A,b,c are three points whose coordinates are (2,2),(-2,-1)and (2,a) such that angle abc is 90 degree .find the value of A and also find abc​

Answer 1

Answer:

given ab is perpendicular to BC

slope of ab = (2-(-1))/(2-(-2))

= (2+1)/(2+2)/

= 3/4

slope of bc = (a-(-1))/((2-(-2))

= (a+1)/(2+2)

= (a+1)/4

since the lines are perpendicular

product of slopes = -1

(a+1)/4* 3/4 = -1

3a + 3 = -16

3a = -19

a = -19/3

I didn't get what is meaning of find abc, if it is area of ∆abc, we can find it using determinants

| 2. 2. 1 |

= 1/2 |-2. -1. 1 |

| 2. -19/3. 1 |