I really do not know how to do this problem, please help!

a. 12.56 mm²

Step-by-step explanation:

hi there,

area of circle = pi r ²

given=

pi= 3.14

radius = 4 mm

putting in formula,

we get 3.14 × 4 =

= 12.56 mm²

Hello! i hope this
since the cosine is the ratio of the adjacent side to the hypotenuse, you can see that cos 60° = ½. answer. according to the property of cofunctions (topic 3), sin 30° is equal to cos 60°. sin 30° = ½.