Joan needs to estimate the size of her bedroom so that she can buy enough paint to cover the walls. Two of the walls measure 2.86 m by 3.16 m, and the other two walls measure 2.86 m by 3.42 m. a) Estimate the area that Joan needs to paint in m b) If one tin of paint will cover 15 m², how many tins of paint will Joan need to paint her bedroom?