Figure is attached below:
Answer:

Step-by-step explanation:
<u>Given Data:</u>
triangle vertices= A,B,C=(0,0), (7,0), (0,7)
<u>Required: Find Volume of the solid=V=?</u>
For this type of question we need to use the following formula of slicing method

where a and b are limits which shows that solid extends from
with the known cross section area
perpendicular to x-axis.
From the Figure.2 we can see that limits are from
to
and the red line is the diameter of the given semi circle.
We can see that if x increases then the diameter decreases along the hypotenuse thus diameter of the semi circle

Radius is half of the diameter, so Radius of semi circle
Here, Area
is the area of the semi circle
so 
Putting values, we get

Putting values in Eq(1), we get


expanding formula (
)



Putting
we get everything zero that's why only have expression for value of
as:


