Question

Perimeter of triangle whose vertices are $(0,4,0),(3,4,0)$ and $(0,4,4)$, is

• A. $10$
• B. $12$
• C. $25$
• D. $15$

Answer 1

Answer: (B)

$12$

Vertices of triangle are $(0,4,0),(3,4,0)$ and $(0,4,4)$

then perimeter=?

here AB=$\sqrt{(3-0{)}^2+(4-4{)}^2+(0-0{)}^2}$

$=3$

BC$=\sqrt{(3-0{)}^2+(4-4{)}^2+(0-4{)}^2}$

$=\sqrt{9+16}$

$=5$

CA$=\sqrt{(0-0{)}^2+(4-4{)}^2+(0-4{)}^2}=4$

used distance formula b/w two points

$(x_1,y_1,z_1)and(x_2,y_2,z_2)$

$=\sqrt{(x_2-x_2{)}^2+(y_2-y_1{)}^2+(z_2-z_1{)}^2}$

$perimeter=ABC+BC+CA$

$=3+5+4$

$=12units$