Answer:
10 units
Step-by-step explanation:
Given that:
Cos a = 3 /5
From trigonometry ;
Cos θ = Adjacent / hypotenus
Side Adjacent angle a = 3 = FD
Hypotenus = 5 = DE
3 / 5 = FD / DE
FD = 6 units
3/5 = 6/DE
DE * 3/5 = 6
DE = 6 ÷ 3/5
DE = 6 * 5 /3
DE = 30 /3
DE = 10 units
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:
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.