Making TrianglesSend reedback9 points are marked on a straight line and 7 points aremarked on another line which is parallel to the first line.How many triangles can you make by joining thesepoints? About the author Madeline
Triangle is formed by picking 3 point 2 from 1 st line and 1 from 2 nd of 1 point from 1 st line or 2 from 2 nd i.e. ⇒ 10 C 2 × 11 C 1 + 10 C 1 + 11 C 2 = 2!8! 10! × 1!10! 11! + 1!9! 10! × 2!9! 11! ⇒45×11+10×55 =495+550=1045 I hope this helps u mark me as brainelist Reply
Triangle is formed by picking 3 point 2 from 1
st
line and 1 from 2
nd
of 1 point from 1
st
line or 2 from 2
nd
i.e.
⇒
10
C
2
×
11
C
1
+
10
C
1
+
11
C
2
=
2!8!
10!
×
1!10!
11!
+
1!9!
10!
×
2!9!
11!
⇒45×11+10×55
=495+550=1045
I hope this helps u
mark me as brainelist