Perimeter Perimeter Given (a+b+c)=k Find Maximum area of triangle (a=b=c) Put value of side a Put value of side b Value of side c Value of angle ∠c between a & b in radian Value of angle ∠c between a & b in degree Area of Triangle-▲ % area of ▲ / maximum area of ▲ 3rd side of triangle can be found from solution of the following  equation :Ax4 + Bx2  + C=0   or   x4 +x2  +=0 Solution : x4 Solution : x4a Solution : x3 Solution : x3a Maximum area of quadrilateral (a=b=c=d) side a side b angle between a & b in degree diagonal e side c side d area of triangle abe area of triangle cde area of quadrilateral % area of ▮ / maximum area of ▮ Maximum area of Rectangle(side1=side2) Put value of one side Value of other side Area of Rectangle- % area of ▮ / maximum area of ▮ area of Circle Radius of Circle semi-major + semi-minor axis≅k/PI  of Ellipse Semi -major Axis (a4) Semi-minor Axis (b4) Find discount factor upto 3rd term h/4 + h2 / 64 + h3 /256 +.....+.....infinite series) where h=(a-b/a+b)2 Revised Semi -major Axis Revised Semi -minor Axis Revised Perimeter Area of Ellipse % area of ellipse / maximum area of ellipse *To find side c of a triangle when a,b are given and in between angle say θ is given . area=(ab/2)sinθ .Now area formula from the sides is (X1+c)(X2+c)(-X2+c)(X1-c) =16 A*A where X1=a+b,X2=b-a; simplifying, c4 -(X12 +X22)c2 +[(X12 *X22 )+16A*A]=0 or c*c=y and y2 -(X12 +X22)y +[(X12 *X22 )+16A*A]=0  or Ay2 +By+C=0 where A=1, B = -(X12 +X22) =-2(a*a+b*b) and C=[(X12 *X22 )+16A*A]  = (a+b)2*(b-a)2 +16A*A; * in ellipse, R=(peri-R)*dfactor or R=peri*dfactor/(1+dfactor)