 # Volume of Triangular Prism excel formula

Hi, Can someone please create an excel formula for the follow equations:  4 Replies

# Re: Volume of Triangular Prism excel formula

Let's say you enter the values for a, b, c and h in B1, B2, B3 and B4, respectively.

In another cell, say B5, enter the formula

=B4/4*SQRT((B1+B2+B3)*(B2+B3-B1)*(B3+B1-B2)*(B1+B2-B3))

or

=B4/4*SQRT(-B1^2+2*(B1*B2)^2+2*(B1*B3)^2-B2^2+2*(B2*B3)^2-B3^2)

# Re: Volume of Triangular Prism excel formula

I would like to simplify the expression.

Suppose a, b, c, h are inputted in B1, B2, B3, B4.

Then in B5, input the formula "=SUM(B1:B3)"

In order to find the volume, you may consider the following formula:

=(B4/4)*SQRT(B5*(B5-2*B1)*(B5-2*B2)*(B5-2*B3))

# Re: Volume of Triangular Prism excel formula

@Man Fai Chan Your formula worked! Thanks!

# Re: Volume of Triangular Prism excel formula

=B4/4*SQRT(-B1^2+2*(B1*B2)^2+2*(B1*B3)^2-B2^2+2*(B2*B3)^2-B3^2)

Incorrect. Three typos and a translation mistake.  Errata:

=B4/4*SQRT(-(B1^4)+2*(B1*B2)^2+2*(B1*B3)^2-B2^4+2*(B2*B3)^2-B3^4)

Note:  In Excel, -B1^4 is parsed as (-B1)^4, which is always positive.  But in math, it is parsed as -(B1^4), which is always negative.

PS.... In selecting a, b and c, we must avoid SQRT returning #NUM because its parameter is negative.  An online calculate [*] specifies the following requirements:

a+b > c
a+c > b
b+c > a

One set of values that meets those conditions:

a: 123
b: 456
c: 543