It is a hot day in summer. A lion is walking along a lake. He is looking for something to eat. He is very hungry. A duck is swimming in the river. The lion is very excited to see him. ‘Aha, there is my lunch,' the lion says to himself.

    "Hello, Mr Duck!" "Go away, bad lion!" says the duck. "I have good news for you." "What is it?" asks the duck. "I don't want other animals to hear it. Please come here." says the lion. The duck swims out of the river and runs to the lion. The lion eats him up quickly.

阅读下文，完成问题

       陆象山少年时，常坐临安市肆观棋，如是者累日。棋工曰：“官人日日来看，必是高手，愿求教一局。”象山曰：“未也。”三日后却来，乃买棋局一副，归而悬之室中。卧而仰视之者两日，忽悟曰：“此《河图》数也。”遂往与棋工对，棋工连负二局。乃起谢曰：“某是临安第一手棋，凡来着者，皆饶一先。今官人之棋，反饶得某一先，天下无敌手矣。”象山笑而去。

      【注】①陆象山，南宋哲学家。②肆：店铺。③河图：介绍占卜等内容的书。④某：我。

“十一五”时期，中国经济发展需要注意解决7大问题，其中之一：进一步鼓励非公有制经济的大力发展，优化社会资源配置。我国进一步鼓励非公有制经济的大力发展，其根本原因在于 （）

（Ⅰ）求C；

（Ⅱ）若c= $\sqrt{7}$ ，△ABC的面积为 $\frac{3\sqrt{3}}{2}$ ，求△ABC的周长．