You have to consider the place in what size. 

以上句子是错误的

应该改为

You have to consider what the place is .

what主要以下几个用法

(1)特殊疑问词用法:引导特殊疑问句，在句子作主语，宾语，表语，定语，补语

What are you doing? 你在做什么？

What subjects did you enjoy most? 你最喜欢什么学科？

What colour is the new carpet? 新地毯是什么颜色的？

What’s your new boss like? 你的新老板怎么样？

What do you think of my painting? 你觉得我的画怎样？

What do you mean, you want to spend Christmas alone? 你是什么意思，你想一个人过圣诞节？

(2)连接代词用法：引导4大名词性从句（引导疑问分句）

What that kid needs is some love and affection. 

那个孩子需要的是一些爱和关怀。

What we’ll do is leave a note for Mum to tell her we won’t be back till late. 我们要做的是给妈妈留一张便条，告诉她我们要很晚才回来。

What matters is the British people and British jobs. 

重要的是英国的人民和英国的就业机会。

No one knows exactly what happened. 没人确切地知道发生了什么事。

(3)融合性关系代词用法：引导关系分句

Show me what you bought. 给我看看你买的东西。

I believe what he told me. 我相信他对我说的话。

I could get you a job here if that’s what you want. 

我可以给你在这里找份工作，如果这就是你想要的。

What he did was morally wrong. 他的行为很缺德。

She gave him what money she had (= all the money she had, although she did not have much ). 她把她仅有的钱全都给了他。

(4)引导感叹句

What a lovely day!,What a horrible thing to do!,What nice people they are! 

多好的天气！,做这种事真可怕！,他们是多好的人啊！