2 cos 30 ° cos 20 ° − 2 cos 40 ° sin 10 ° − 2 cos 20 ° sin 10 ° 2 cos ⁡ 30 ° cos ⁡ 20 ° - 2 cos ⁡ 40 ° sin ⁡ 10 ° - 2 cos ⁡ 20 ° sin ⁡ 10 ° =?

You have 2 sides that are 2 cms and you have 6 sides that are 1/2 cm and you have 4 sides that are 1 cm. the smallest sides are 1/2 the medium sized sides are 1 and the smallest are 1/2. so to find the perimeter you have to add them all up together so your answer will be 11 cm's