Sin 20° · sin 40° · sin 80° = 1/2 ( cos 20° - cos 60° ) · sin 80° =
= 1/2 ( cos 20° sin 80° - cos 60° sin 80° ) =
= 1/2 ( (sin 100° + sin 60°)/2 - 1/2 sin 80° )= ( sin 100° = sin 80° )
= 1/2 · ( 1/2 sin 60° ) = 1/4 sin 60° = √3 / 8
sin 60° = √ 3/2
√ 3 / 2 · √ 3 / 8 = 3/16 ( correct )
Opposite lateral faces of a rectangular pyramid are congruent.
I think is OPPOSITE .
Answer:
5
Step-by-step explanation:15×5
Answer:
Step-by-step explanation:
"length is 4 meters less than 2 times the width"
L = 2W+4
"perimeter is 40 meters"
2L+2W = 40
L+W = 20
(2W+4) + W = 20
3W + 4 = 20
W = 16/3 meters
Answer:
Step-by-step explanation: Answer is A
