So yuo simplyfly
15:20=3:4
6:8=3:4
8:12=2:3
9:12=3:4
so your answer is not c
The answer is a^2 + 5a - 104 I think
A²+b²=c², a=opposite b=adjacent c=hypotenuse
a=3,c=√34
3²+b²=√34²
9+b²=34
-9 -9
√b²=√25
b=5
So the formula for area of a triangle is A= 1/2 base x height. SO you do 20 x 30 you get 600. 600/ 2 = 300 so 300 km squared.
