The base of a triangular pyramid is a triangle with corners at (3 ,9 ), (1 ,6 ), and (2 ,8 ). If the pyramid has a height of 4 , what is the pyramid's volume?

1 Answer
Mar 18, 2016

Volume of pyramid is 0.661 units.

Explanation:

First to find area of base, let us find all the sides of base triangle.

a=sqrt((1-3)^2+(6-9)^2)=sqrt(4+9)=sqrt13=3.606

b=sqrt((2-3)^2+(8-9)^2)=sqrt(1+1)=sqrt2=1.414

c=sqrt((2-1)^2+(8-6)^2)=sqrt(1+4)=sqrt5=2.236

Now for using Heron's formula, s=1/2(3.606+1.414+2.236)=7.256/2=3.628

Hence, area of base triangle is

sqrt(3.628xx(3.628-3.606)xx(3.628-1.414)xx(3.628-2.236)

= sqrt(3.628xx0.022xx2.214xx1.392)=0.496

Hence, Volume of pyramid is 1/3xx0.496xx4=0.661