This is a classic example of a 45-45-90 triangle: it's a right triangle (one angle of 90) & two other sides of the same length, which means two angles of the same length (and 45 is the only number that will work). With a 45-45-90 triangle, the lengths of the legs are easy to determine:
45-45-90
1-1-sqrt2
Where the hypotenuse corresponds to sqrt2.
Now, your hypotenuse is 10.
To figure out what each leg is, divide 10/sqrt2 (because sqrt2/sqrt2 = 1, which is a leg length in the explanation above).
Problem: you can't divide by radicals. So, we'll have to rationalize the denominator:
(10•sqrt2)/(sqrt2•sqrt2)
This can be rewritten:
10sqrt2/sqrt(2•2)
=10sqrt2/sqrt4
=10sqrt2/2
=5sqrt2
Hope this helps!!
Step-by-step explanation:
Given prism has:
Length = 5 in, width = 4 in & height = 6 in
Surface area of prism

Problem 10
You are correct. You divide 360 over the exterior angle measure to get 360/72 = 5
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Problem 11
x = 33 is correct as this angle is an alternate interior angle pair with the 33 degree angle up top
y = 38 is correct since y+33+109 = 180 solves to y = 38. In other words: 38+33+109 = 180
z = 109 is correct. The opposite angles of a parallelogram are congruent