Step-by-step explanation:
3
Let D be the mid point of side BC, [B(2, - 1), C(5, 2)].
Therefore, by mid-point formula:
![D = ( \frac{2 + 5}{2}, \: \: \frac{ - 1 + 2}{2} ) = ( \frac{7}{2}, \: \: \frac{ 1}{2} ) \\ \therefore D= (3.5, \: \: 0.5) \\ \& \: A=(-1,\:\:4)...(given) \\\\ now \: by \: distance \: formula \\ \\ Length \: of \: segment \: AD \\ = \sqrt{( - 1 - 3.5)^{2} + {(4 - 0.5)}^{2} } \\ = \sqrt{(4.5)^{2} + {(3.5)}^{2} } \\ = \sqrt{20.25 + 12.25 } \\ = \sqrt{32.5} \\ \red{ \boxed{\therefore Length \: of \: segment \: AD = 5.7 \: units}}](https://tex.z-dn.net/?f=D%20%3D%20%28%20%5Cfrac%7B2%20%2B%205%7D%7B2%7D%2C%20%20%5C%3A%20%20%5C%3A%20%20%5Cfrac%7B%20-%201%20%2B%202%7D%7B2%7D%20%29%20%3D%20%28%20%5Cfrac%7B7%7D%7B2%7D%2C%20%5C%3A%20%20%5C%3A%20%20%5Cfrac%7B%201%7D%7B2%7D%20%29%20%5C%5C%20%5Ctherefore%20D%3D%20%283.5%2C%20%5C%3A%20%20%5C%3A%200.5%29%20%5C%5C%20%20%5C%26%20%5C%3A%20A%3D%28-1%2C%5C%3A%5C%3A4%29...%28given%29%20%5C%5C%5C%5C%20%20now%20%5C%3A%20by%20%5C%3A%20distance%20%5C%3A%20formula%20%5C%5C%20%20%5C%5C%20Length%20%20%5C%3A%20of%20%5C%3A%20%20segment%20%20%5C%3A%20AD%20%5C%5C%20%20%3D%20%20%5Csqrt%7B%28%20-%201%20-%203.5%29%5E%7B2%7D%20%20%2B%20%20%7B%284%20-%200.5%29%7D%5E%7B2%7D%20%7D%20%20%5C%5C%20%3D%20%20%5Csqrt%7B%284.5%29%5E%7B2%7D%20%20%2B%20%20%7B%283.5%29%7D%5E%7B2%7D%20%7D%20%20%5C%5C%20%3D%20%20%5Csqrt%7B20.25%20%2B%2012.25%20%7D%20%20%5C%5C%20%20%3D%20%20%5Csqrt%7B32.5%7D%20%20%5C%5C%20%20%20%20%5Cred%7B%20%5Cboxed%7B%5Ctherefore%20Length%20%20%5C%3A%20of%20%5C%3A%20%20segment%20%20%5C%3A%20AD%20%20%3D%205.7%20%5C%3A%20units%7D%7D)
4 (a)
Equation of line AB[A(2, 1), B(-2, - 11)] in two point form is given as:
is the equation of line AB.
Now we have to check whether C(4, 7) lie on line AB or not.
Let us substitute x = 4 & y = 7 on the Left hand side of equation of line AB and if it gives us 0, then C lies on the line.
Hence, point C (4, 7) lie on the straight line AB.
4(b)
Like we did in 4(a), first find the equation of line AB and then substitute the coordinates of point C in equation and if they satisfy the equation, then all the three points lie on the straight line.