5(n-4)=(4n-12)
First: Distribute 5 into n and -4.
5(n-4)=(5n)+(5*-4)= 5n-20.
Second: Subtract 4n from both sides to eliminate the variable from the right side of the equation.
(5n-20)=(4n-12)
n-20=-12
Next: Add 20 to both sides to eliminate the constant from the left side of the equation.
n-20=-12
n=8
The unknown number is 8.
Well the only right triangle with two similar sides is a special triangle called a 45 45 90. After the degrees of its shape
_
two sides are x and the other is x/2 _
so in this case the other angle would be 20/2 [20 root (2), its hard to draw roots on this site so I thought I would clarify that was what I was drawing]
Hope this helps, good luck.
25/12.5 = 40/y
cross multiply
(25)(y) = (12.5)(40)
25y = 500
y = 500/25
y = 20 <====