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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.
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.
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