Answer:
-84
Step-by-step explanation:
The formula for the nth term of a geometric progression is
Un = ar^n- 1
The sum of the first six terms of a geometric series (U6) = 21/16
Common ratio = -1/2 ,
a = First term ??
21/16 = a × (-1/2 )^6- 1
21/16 = a ×(-2^-1)^5
21/16 = a × -2^-6
Cross Multiply
16 × a × -2^-6 = 21
a = 21/16 × -2^-6
a = 21/16 ×- 1/2⁶
a = 21/16 × -1/64
a = 21 ÷(-1/4)
a = 21 × -4
a = -84
The first term = 84
Answer:
can't see it
Step-by-step explanation:
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You know that you have the Opposite side and the Adjacent side. therefore you would use Tangent (T= O/A)
because you are finding the angle you would go Tan^-1(12÷20) =31°
it is 12÷20 because O/A and the 12 is the opposite side therefore It would be O and 20 is the adjacent side therefore equaling 20 so O/A = 12/20
Your answer is 31°
Area of triangle = 1/2 x base x height
Let the base be "b"
90 = 1/2 x 10 x b
90 = 5b
b = 18 ft
Base = 18 ft