Step-by-step explanation:
in a geometric sequence there is a constant factor x that is multiplied with every previous term to create the next one.
a2 = 20
a5 = 1280 = a2×x×x×x = a2×x³ = 20x³
64 = x³
x = 4
=> a1 = 5
therefore
an = an-1×4 =

n > 1
Answer:
Area = 3*3 + 3*4 = 9 + 12 = 21
It is number 3. Have a good day.
Answer:
5 x 2 x 3.14 = 31.4
Formula of circumference:
radius(half of your diameter or given radius) x pi(3.14 or 22/7 depending on what they tell you to use for pi) x 2(just always there when finding circumference)
The triangles are isosceles. The following notation are for the angles. For example ABD is refer to the angle located in the B vertex, formed by the segments AB and BD.


Then
