Answer:
Because the sides BO and MA are marked with one line through the middle, which means those sides are congruent, angle A and Angle O are marked with one line, the angles are congruent, and angles W and N are marked with two lines, which means they are congruent. Therefore the triangles are congruent
<span>I : 2n + 1
II : 2n + 3
III : 2n +5
(2n + 1) + (2n + 3) +(2n+5)=63
6n+9=63
n=9
I : 2n+1=9*2+1=19
II : 2n+3=9*2+3=21
III : 2n+5=9*2+5=23
19+21+23=63
</span>
Answer: B
from the first image, the opposite of B is D. so whenever its rotated somehow, D is going to fall on the opposite of B. Therefore when B is at the top, D should be at the opposite on the bottom. Thus we found our answer. B is the correct answer. others are eliminated.
<span> sin20 * sin40 * sin60 * sin80
since sin 60 = </span><span> √3/2
</span>√3/<span>2 (sin 20 * sin 40 * sin 80)
</span>√3/<span>2 (sin 20) [sin 40 * sin 80]
</span>
Using identity: <span>sin A sin B = (1/2) [ cos(A - B) - cos(A + B) ]
</span>√3/<span>2 (sin 20) (1 / 2) [cos 40 - cos 120]
</span>√3/4<span> (sin 20) [cos 40 + cos 60]
</span>
Since cos 60 = 1/2:
√3/4<span> (sin 20) [cos 40 + (1/2)]
</span>√3/4 (sin 20)(cos 40) + √3/8<span> (sin 20)
</span>
Using identity: <span> sin A cos B = 1/2 [ sin(A + B) + sin(A - B) ]
</span>√<span>3/4 (1 / 2) [sin 60 + sin (-20)] + </span>√3/8<span> (sin 20)
</span>
Since sin 60 = √3/<span>2
</span>√3/8 [√3/2 - sin 20] + √3/8 (sin 20)
3/16 - √3/8 sin 20 + √3/8<span> sin 20
</span>
Cancelling out the 2 terms:
3/16
Therefore, sin20 * sin40 * sin60 * <span>sin80 = 3/16</span>
