Question

find the value of coses 30 geometrically

Answer 1

For finding the value of sin 300geometrically, we construct an equilateral triangle ABC of side 2 a. From A, we draw perpendicular AD to BC. Now, BD = CD = 1/2 BC = a

In triangle ABD, BAD + BDA + DAB = 180 (BY ANGLE SUM PROPERTY)

=== 600+ BAD + 900= 1800(SINCE AD | BC AND ALL ANGLES ARE 600in a equilateral triangle)

=== BAD = 300

IN RT TRIANGLE BAD,

SIN 300= BD / AB= a / 2 a= 1/ 2

hence geometrically shown that sin 30 is 1/2