00:01
For problem five, it says that a small staircase is made so that the horizontal piece of each step is 10 inches long.
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So this part is 10 inches and 25 inches wide up here.
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And each step is five inches above the previous one.
00:22
So these are all five.
00:27
It wants us to determine what the surface area of this small staircase is.
00:33
So the first thing i'm going to find the area of is back.
00:37
Here.
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Now because these are each five inches, this whole side length here would be 15.
00:48
So i would do 15 times 25 to get the back rectangle, which is 375.
01:02
So then i'm going to go over here and get this portion on the right hand side.
01:09
So because each of these are 10 by 5, i can go ahead and into 10 by 5 right here, which would be 50.
01:21
Now over here, this would be 20 by 5 in this section.
01:26
20 times 5 is 100...