The calculation formula of trapezoid area is s = 1 divided by 2 (a + b) h. It is known that a = 4. H = 8. S = 40. Find the value of B One divided by two is one in two

It's very simple
The area formula is
s=(a+b)*h/2
Substituting a = 4, H = 8, s = 40
(4+b)*8/2=40
Just solve the equation
(4+b)*8/2=40
16+4b=40
4b=24
b=6
So B = 6

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