I have a triangle. Ok lol. They gave me the points
A ( - 2, 0)
B ( 0, 4)
C (8, 0 )
and It says Show that the angle of the roof peak iS 90 DEGREES
how am i supposed to do that?
2006-11-26 05:14:29 · 5 answers · asked by Jazz 2 in Science & Mathematics ➔ Mathematics
You are given the points of the triangle, so you can determine the slope of each side. Slope is rise/run or (Y1-Y2) / (X1-X2).
Slope of AB is (0 - 4) / (-2 - 0) = -4 / -2 = 2
Slope of BC is (4 - 0) / (0 - 8) = 4 / -8 = -1/2
Slope of AC is (0 - 0) / (-2 - 8) = 0 / -10 = 0
Since the slope of AB is the inverse and negative of slope BC, then line AB and line BC must be at a right angle.
2006-11-26 05:26:37 · answer #1 · answered by Spaghetti Cat 5 · 0⤊ 0⤋
Draw this triangle and look: OA^2+OB^2=AB^2 or 4+16=20, OC^2+OB^2=BC^2 or 64+16=80. Now AB^2+BC^2 must be = to AC^2. AC=10, AC^2=100=20+80. YES 90.
If you know vectors. Vector AB=(0-(-2))*i +(4-0)*j, AC=(8-0)*i + (0-4)*j. Now scalar product (AB*AC)= 2*8+4*(-4)=0 means that AB is normal to AC.
2006-11-26 15:56:09 · answer #2 · answered by Anonymous · 0⤊ 0⤋
AB^2=4^2+2^2=20
BC^2=(-4)^2+8^2=80
AC^2=10^2=100
since AC^2=AB^2+BC^2 it is a rt triangle
right angled at B
2006-11-26 13:17:22 · answer #3 · answered by raj 7 · 0⤊ 0⤋
Find the lengths of AB, BC, and AC (with the distance formula or another method) and then prove that the Pythagorean theorem (a^2 + b^2 = c^2) is true for the triangle.
Hope that helped.
2006-11-26 13:19:56 · answer #4 · answered by Anonymous · 0⤊ 0⤋
apply vector
dot product
2006-11-26 13:26:08 · answer #5 · answered by n nitant 3 · 0⤊ 0⤋