Answer:
c) 7π cm
Explanation:
The length of an arc (s) is related to its central angle (θ) and the radius of the circle (r) by ...
... s = rθ . . . . . . . . . θ in radians
Here, the central angle measures are given in "grads". There are 400 grads in a circle, so 200 grads in π radians. To convert grads to radians, we multiply the number of grads by π/(200g).
Then the lengths of the arcs are ...
... arc AB = (20 cm)·(50g·(π/(200g))) = 5π cm
... arc BC = (10 cm)·(40g·(π/(200g))) = 2π cm
E = arc AB + arc BC = 5π cm + 2π cm = 7π cm