Q. 24.0( 2 Votes )
The vertices of a triangle ABC are A(0, 0), B (2, -1) and C (9, 0). Find cos B.
Key points to solve the problem:
• The idea of distance formula- Distance between two points P(x1,y1) and Q(x2,y2) is given by- PQ =
Coordinates of the triangle and we need to find cos B which can be easily found using cosine formula.
See the figure:
From cosine formula in ΔABC , We have:
cos B =
using distance formula we have:
And, AC =
∴ cos B = …ans
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