Please help I don't know how to find area so please help
1 answer:
I think that you should imagine what regular shape the figure would have been.
The fact that two sides are 9inches makes me think it would have been a square.
The area of a square is A= l² where l is the length of one side and A=area
A=9*9
A=81 in.²
Next, find the area of the part that is taken away,(it looks like a triangle). to find that, if the figure was a square, the length on top would be 9 not 5, so the length gone is 9-5=4, so the base of the triangle is 4,
If the figure was a square, the length on the other side would be 9 not 4 so the length gone is 9-4=5, so the height of the triangle is 5
the area of a triangle is A= 1/2bh, where A is area, b is base and h is height.
A=1/2*4*5 A=10 so the area of the part gone is 10 inches²
The area of the figure is the area of the square -the area of the triangle
A=81-10
A=71inches²
,
The fact that two sides are 9inches makes me think it would have been a square.
The area of a square is A= l² where l is the length of one side and A=area
A=9*9
A=81 in.²
Next, find the area of the part that is taken away,(it looks like a triangle). to find that, if the figure was a square, the length on top would be 9 not 5, so the length gone is 9-5=4, so the base of the triangle is 4,
If the figure was a square, the length on the other side would be 9 not 4 so the length gone is 9-4=5, so the height of the triangle is 5
the area of a triangle is A= 1/2bh, where A is area, b is base and h is height.
A=1/2*4*5 A=10 so the area of the part gone is 10 inches²
The area of the figure is the area of the square -the area of the triangle
A=81-10
A=71inches²
,
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Answer:
Solution ( Second Attachment ) : - 2.017 + 0.656i
Solution ( First Attachment ) : 16.140 - 5.244i
Step-by-step explanation:
Second Attachment : The quotient of the two expressions would be the following,
÷
So if we want to determine this expression in standard complex form, we can first convert it into trigonometric form, then apply trivial identities. Either that, or we can straight away apply the following identities and substitute,
( 1 ) cos(x) = sin(π / 2 - x)
( 2 ) sin(x) = cos(π / 2 - x)
If cos(x) = sin(π / 2 - x), then cos(2π / 5) = sin(π / 2 - 2π / 5) = sin(π / 10). Respectively sin(2π / 5) = cos(π / 2 - 2π / 5) = cos(π / 10). Let's simplify sin(π / 10) and cos(π / 10) with two more identities,
( 1 )
( 2 )
These two identities makes sin(π / 10) = , and cos(π / 10) =
.
Therefore cos(2π / 5) = , and sin(2π / 5) =
. Substitute,
÷
Remember that cos(- π / 2) = 0, and sin(- π / 2) = - 1. Substituting those values,
÷
And now simplify this expression to receive our answer,
÷
=
,
=
and
=
=
As you can see our solution is option c. - 2.01749 was rounded to - 2.017, and 0.65552 was rounded to 0.656.
________________________________________
First Attachment : We know from the previous problem that cos(2π / 5) = , sin(2π / 5) =
, cos(- π / 2) = 0, and sin(- π / 2) = - 1. Substituting we receive a simplified expression,
We know that and
. Therefore,
Solution :
Which rounds to about option b.