To find the resultant force \(R\) and the angle \(\alpha\), we resolve the forces into their horizontal and vertical components.

Horizontal component, \(X = 100 + 250 \cos 70^\circ\)

Vertical component, \(Y = 300 - 250 \sin 70^\circ\)

Calculate \(X\) and \(Y\):

\(X = 100 + 250 \times 0.3420 = 185.5\)

\(Y = 300 - 250 \times 0.9397 = 65.1\)

The magnitude of the resultant force \(R\) is given by:

\(R^2 = X^2 + Y^2\)

\(R^2 = 185.5^2 + 65.1^2\)

\(R = \sqrt{185.5^2 + 65.1^2} = 197\)

The angle \(\alpha\) is given by:

\(\tan \alpha = \frac{Y}{X} = \frac{65.1}{185.5}\)

\(\alpha = \arctan \left( \frac{65.1}{185.5} \right) = 19.3^\circ\)