The two forces are the legs of a right triangle, and the resultant is
the hypotenuse of the triangle.
Its length = √ (30N)² + (40N)²
= √ (900 N² + 1600 N²)
= √ (2500 N²) = 50 N .
Using a scale of 1 cm to represent 10 N, you would draw
the resultant force with an arrow 5 cm long.
To describe the direction of the arrow, we first have to describe
the directions of the 30N and the 40N. Let's say that from where
we're standing, the 30N is pushing us to the RIGHT, and the 40N
is pushing us UP.
You can see that when the two forces push at the same time,
we'll be pushed in a direction somewhere to the right of up.
If you sketch the force triangle on paper, you'll see that the angle
between the 30N force and the hypotenuse has a sine of 0.6 (30/50),
a cosine of 0.8 (40/50), and a tangent of 1.333 (40/30).
You can use any one of these numbers to find the value of the angle.
On your calculator, type in the number you choose, then tap the
sin⁻¹ key, the cos⁻¹ key, or the tan⁻¹ key, and the angle pops up.
The angle is 25.32 degrees.
That's the angle between (straight to the right) and the resultant force.
Draw the arrow pointing 25.32° above straight-to-the-right.
