1) 260 km/h
Let's use the following convention:
positive x-direction = east
positive y-direction = north
Here we have to find the north component of the velocity's airplane, which means we have to find its y-component.
We can use the formula:
![v_y = v sin \theta](https://img.qammunity.org/2020/formulas/physics/middle-school/feosemg1fud4dj7172omx8z3ihoinzkjb6.png)
where
v = 750 km/h is the magnitude of the plane's velocity
is the angle between the direction of the plane and the positive x-axis
Substituting,
![v_y = (750)(sin 20)=256.5 km/h \sim 260 km/h](https://img.qammunity.org/2020/formulas/physics/high-school/j6ymz42melyxspx5imue1nar6xkx7cttv9.png)
2)
north of east
In order to find the direction of flight, we have to consider that the vector representing the displacement of the plane is the hypothenuse of a right triangle, of which the displacements along the east and north direction are the sides.
Therefore, we have
is the displacement towards east
is the displacement towards north
Therefore, the angle that gives the direction is given by
![tan \theta = (v_y)/(v_x)](https://img.qammunity.org/2020/formulas/physics/high-school/n3mtw4estee52raadr0gp543b0kamrfcoa.png)
And substituting,
![\theta =tan^(-1)( (100)/(200))=24^(\circ)](https://img.qammunity.org/2020/formulas/physics/high-school/gca4eaznmy4ex5p5tbraxyu0xlleomlggs.png)
and this angle is measured north of east.