A piece of wire 40cm long is bent into the form of an arc subtending an angle of 120 degree at the centre. What will be the radius (in cm) of the circle so formed?

Area topics are: Area of rectangles, squares, triangles, quadrilaterals, polygons, and circles.

Here are some area formulas for quantitative aptitude:
Rectangle: Area = (length x breadth)
Square: Area = (side)2 = (diagonal)2
Triangle: Area = x base x height
Parallelogram: Area = (base x height)
Circle: Area = R2, where R is the radius
Trapezoid: Area = 1⁄2 × (base + base) × height
Room walls: Area = 2 (length + breadth) x height
Circumference of a semi-circle: Circumference = R