I would just like to someone to have a quick look at my maths for this question. I do not feel 100% that I am doing it right. Question: Two circles have a radii r cm and 4r cm. Find in terms of ∏ and r a) the area of the circle with radius 4r. Here are my working; by the way still cant get latex to work, I have tried to everything, could someone point me to a latex post to see where I am going wrong. area = ∏*r^2 ====> ∏*(4r)^2 =====> (16∏r^2) b) The area of the shaded ring: area = 16∏r^2 - ∏r^2 = (15∏r^2) c) The total length of the inner and outer edges of the shaded ring. Circumference = 2∏r =====> 2∏4r ======> 8∏r =====> 8∏r + 2∏r = (10∏r) The answers and the ones with brackets. I have attched a drawing of the image that goes with the question. Not sure if really needed.