SOLUTION: Find the value of x, correct to 1 decimal place, in this diagram if the area is to be 20 square units. Diagram: http://imgur.com/a/d2Kdt Here is my working, the answer I got

Question 1055210: Find the value of x, correct to 1 decimal place, in this diagram if the area is to be 20 square units.
Diagram: http://imgur.com/a/d2Kdt
Here is my working, the answer I got is different from the answer in the book which is 1.6
x(x+10)+ 1/2(pi x^2) =20
x^2 +10x + 1/2(pi x^2)= 20
2x^2+20x+pi x^2=40
(2+pi)x^2+20x-40=0
since x>0, x=1.455
Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!
First step is wrong.
Idea of sum of the two area parts is conceptually correct.

NOW you should be able to solve and find a better result.
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