TT13-25

zengxiaotao

In the xy-plane, the vertices of a triangle have coordinates (0,0), (3,3), and (7,0). what is the perimeter of the triangle?

A. 13

B.根号34

C.根号43

D. 7+6根号2

E. 12+3根号2

我求得斜边=根号58，周长=10+根号58，可选项里没这个答案，请各位多多赐教！

JJJooe

（3根号2）+7+5=12+3根号2

 

judy_zhaoli

不是 10+v(58), 应该是 12+3v(2).  你想想, 底边是7, 靠左边的那个斜边是 更号(3^2+3^2)= v(18)=3v(2), 靠右边的那个是5, 因为是直角, 另两边是3 and 4.  So, the perimeter should be 5+7+3v(2) = 12 + 3v(2). It's E.