Perimeter and Areas of Rectangle, Area of Traingles and Paralellograms, and Circles (area, radius, diameter, and circumference)

What’s the perimeter formula of a rectangle?

2L+2W=P

What’s the area formula of a rectangle?

L\cdot W=A

What’s the area formula for a parallelogram?

B\cdot H=A

What’s the area formula for a triangle?

\frac12\left(B\cdot H\right)=A

What’s the circumference formula of a circle?

\pi\left(2\cdot r\right)=c

\pi\cdot d=c

What’s the diameter formula of a circle?

2\cdot r=d

What’s the area formula of a circle?

\pi\cdot r^2=A

What’s the radius formula of a circle?

\frac{d}{2}=r