Octagon eight lines of reflective symmetry and rotational symmetry of order 8. A regular octagon is represented by the Schläfli symbol {8}. The internal angle at each vertex of a regular octagon is 135° (formula_1 radians). The central angle is 45° (formula_2 radians). The area of a regular octagon of side length "a" is given by In terms of the circumradius "R", the area is In terms of the apothem "r" (see also inscribed figure), the area is These last two coefficients bracket the value of pi, the area of the unit circle. The area can also be expressed as where
Angle deception jamming angles. This pattern is typically represented by measuring the angle where it has one-half the sensitivity as it does on the boresight. This is known as the half power point. This means that a target in a radar beam will return a signal when the antenna is anywhere within a few degrees of the boresight. The pattern is too wide to allow the radar to directly guide weapons, especially anti-aircraft artillery which need accuracy on the order of 0.1 degrees. However, it is possible to use the non-linear pattern to improve the angle measurement using a system known as conical