Find the area: to the nearest whole number

The area of the composite area is 400 square millimeters.

Step-by-step explanation:

The area of the composite figure (), in square millimeters, is found by multiplying the area of the equivalent rectangle, in which a semicircle of the original rectangle is move to the opposite side of the figure, so that quantity of area is conserved:

(1)

Where:

- Width, in millimeters.

- Height, in millimeters.

If we know that , the area of the composite figure is:

The area of the composite area is 400 square millimeters.

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐

12cm

the answer is d