It would be easier for me if you had typed the question in.
I just say this for your future reference.
\(x^2+y^2=50 \qquad \text{Tangent at (1,7)} \)
\(x^2+y^2=50\\ \text{top semicircle}\\ y=(50-x^2)^{0.5}\\ \frac{dy}{dx}=0.5(50-x^2)^{-0.5}*-2x\\ \frac{dy}{dx}=-x(50-x^2)^{-0.5}\\ \text{when x=1}\\ \frac{dy}{dx}=\frac{-1}{7}\\ \)
The gradient of the line is -1/7 and it passses through (1,7)
After checking what i have already done, you can:
1) find the equation of the line.
2) Find the x and y intercepts
2) determine the area of the triangle.
If you do not understand something then you can ask.
I RESPECTFULLY REQUEST that no one else jumps in and finishes this.
It is Homework and the asker will learn more if they have to do some of it themself.
+118667 
