[填空题]
The diagram below shows a triangular u6w,y0x l bvqre5tj;+ hn4qv, backyard fs(k l mb w6ll:.xh71wABC. A dog is on a leash attached to a pole at point A. The length of the leash is:lhxs(f wl bw .k6lm17 10 metres.
1.Find the area of the backyard that the dog cannot reach. $m^2$
The owner of the dog estimates that the area the dog cannot reach is $50 m^2$.
2.Calculate the percentage error in the dog owner's estimate. %
