Can you solve question four for me and figure out what the area of the triangle is?

EXPLANATION:
We are given a triangle with two sides indicated and the third side unknown.
Note that for right angled triangles we can solve for unknown sides by using the Pythagoras theorem as shown;
[tex]\begin{gathered} c^2=a^2+b^2 \\ Where\text{ the variables are;} \\ c=hypotenuse \\ a,b=other\text{ sides} \end{gathered}[/tex]For the first triangle we have the sides a and b as;
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