+63 This question here is giving me a hard time can any help me?
1) which angle in the quadrilateral with vertices A(2,-4),, B(-5,-2),C(-4,2) and D(4,0) is a right angle?
+37158 Slope of the line between (-5,-2) and (-4,2) is rise/run = 4/1 = 4
slope from (-4.2) to (4,0) is rise/run = -2/8 = -1/4
does that give you a clue?
+63 sort of I can see that they are perpendicular, but I am confused. Geometry is just realy hard for me to comprehend.
+130099 A(2,-4),, B(-5,-2),C(-4,2) and D(4,0)
Look at the graph
It seems clear that Angles D and A are not right angles
The slope between C and D = [ 0 - 2] / [ 4 - - 4 ] = -2 / 8 = -1/4
The slope between A and B = [ -2 - - 4 ] / [ -5 - 2] = 2/-7 = - 2/7
The solpe between C and B = [ 2 - - 2 ] / [ -4 - - 5 ] = 4 / 1 = 4
Since CD and CB have negative reciprocal slopes....then angle C is the right angle
+26396 This question here is giving me a hard time can any help me?
1)
which angle in the quadrilateral with vertices A(2,-4),, B(-5,-2),C(-4,2) and D(4,0) is a right angle?
\(\begin{array}{|rcll|} \hline \overline{CD}^2 = 8^2+2^2 = 68 \\ \overline{CB}^2 = 4^2+1^2 = 17 \\ \overline{BD}^2 = 9^2+2^2 = 85 \\ \hline \end{array}\)
Pythagoras:
\(\begin{array}{|rcll|} \hline \overline{CD}^2+\overline{CB}^2 &\overset{?}{=}& \overline{BD}^2 \quad | \quad \text{If true, then C is a right angle!} \\ 68+17 &\overset{?}{=}& 85 \\ 85 &=& 85 \quad | \quad \text{So C is a right angle!} \\ \hline \end{array}\)
