8. $-21 a+28 a-6=-10.2$
10. $68=\frac{1}{5}(20 x+50)+2$

Side lengths: RS=7 and ST=7, and angle=90 degrees
Why?
Since second coordinates of R and S are the same so we can just count the length by adding first coordinate of R and first coordinate of S= |-3|+4=7
Since first coordinates of R is the same as first coordinate of T so we can just count the length by adding second coordinates of S and T=5+|-2|=7
Angle: RST is =90 degrees because triangle RST is right angled triangle. Why? Because RS is parallel to X axis(the same second coordinates of R and S) and ST is parallel to Y axis(the same coordinates of S and T) .

Answered by FileT | 2024-06-10

The side lengths of triangle RST are RS = 7, ST = 7, and RT ≈ 7.07. The angle measures are RST = 90 degrees, SRT = 45 degrees, and RTS = 45 degrees. Triangle RST is a right triangle with sides along the axes of the coordinate plane.
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Answered by FileT | 2024-12-24