In an arithmetic sequence, the first term is 5 and the third term is -5. What is the 20th term?
2 answers:
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Answer:
(d) 71°
Step-by-step explanation:
The desired angle in the given isosceles triangle can be found a couple of ways. The Law of Cosines can be used, or the definition of the sine of an angle can be used.
<h3>Sine</h3>Since the triangle is isosceles, the bisector of angle W is an altitude of the triangle. The hypotenuse and opposite side with respect to the divided angle are given, so we can use the sine relation.
sin(W/2) = Opposite/Hypotenuse
sin(W/2) = (35/2)/(30) = 7/12
Using the inverse sine function, we find ...
W/2 = arcsin(7/12) ≈ 35.685°
W = 2×36.684° = 71.37°
W ≈ 71°
<h3>Law of cosines</h3>The law of cosines tells you ...
w² = u² +v² -2uv·cos(W)
Solving for W gives ...
W = arccos((u² +v² -w²)/(2uv))
W = arccos((30² +30² -35²)/(2·30·30)) = arccos(575/1800) ≈ 71.37°
W ≈ 71°
Answer:
grains of sand are in the Sahara Desert
Step-by-step explanation:
Given :
The Sahara Desert has an area of approximately 9,400,400 sq.km.
Depth = 150 m
To Find :Approximately how many grains of sand are in the Sahara Desert?
Solution:
Area of Sahara desert = 9,400,400 sq.km.
So,
Volume of sand =
=
So,
1 cubic cm holds grains of sand = 8000
holds grains of sand =
=
Hence grains of sand are in the Sahara Desert