The inclination of the straight line DE is 45 degree. D(0,2n), E(m,0)

(a) Express m in terms of n.
(b) If the area of triangleDEO is 18 sq.units, find the values of m and n.

(a) The change in y equals the change in x between the points. Therefore

m = 2n

(b) Where is O ? Is it the origin (0,0) ?

If so, the triangle area is (1/2)*m*2n

18 = m*n = 2n^2
n = 3
m = 6