Answer
A force of $2.4~tons$ holds the monolith on the causeway.
Work Step by Step
Let $F$ be the force directed up the hill that holds the monolith on the causeway.
The monolith's weight of $60~tons$ is directed straight down. The force $F$ is directed up the causeway at an angle of $2.3^{\circ}$ above the horizontal.
We can draw a right angle triangle with $60~tons$ as the hypotenuse of the triangle and the force $F$ opposite the angle of $2.3^{\circ}$.
We can find the force $F$:
$\frac{F}{60~tons} = sin~2.3^{\circ}$
$F = (60~tons)~sin~2.3^{\circ}$
$F = 2.4~tons$
A force of $2.4~tons$ holds the monolith on the causeway.
