**4.b.1 - 2015 Q4**

Figure 1 shows a sketch of a design for a scraper blade. The blade

(a) Show that the angle

(b) Find the perimeter of

(c) Find the area of

*AOBCDA*consists of an isosceles triangle*COD*joined along its equal sides to sectors*OBC*and*ODA*of a circle with centre*O*and radius 8 cm. Angles*AOD*and*BOC*are equal.*AO*B is a straight line and is parallel to the line*DC*.*DC*has length 7 cm.(a) Show that the angle

*COD*is 0.906 radians, correct to 3 significant figures. (2)(b) Find the perimeter of

*AOBCDA*, giving your answer to 3 significant figures. (3)(c) Find the area of

*AOBCDA*, giving your answer to 3 significant figures. (3)