<h2>
Answer:</h2>
The number of kilograms a 19 m beam can support is:
378.9474 kg
<h2>
Step-by-step explanation:</h2>
It is given that:
The weight W that a horizontal beam can support varies inversely as the length L of the beam.
Let k denote the constant.
This means that the weight W and Length L is related as:

Suppose that an 8 dash m beam can support 900 kg.
This means that L=8 and W=900
Then,

Now , we are asked to find the value of W when L= 19
i.e.

A^2 + b^2= c^2
(a,b,c are right triangle sides)
A=h*b/2
180 =(b-2)*b/2
360 = b^2-2b
b^2 -2b -360 =0
D = 4+1440 = 1444
b_1,2 = (2+/-sqrt1444)/2 = -18 and 20
base length equal 20 in
height equal 18 in
hope helped