Mathematics
9 Online
OpenStudy (rianiscool):
need help asap will give a medal
What is the area of the figure?
A.
24 km²
B.
32 km²
C.
40 km²
D.
48 km²
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OpenStudy (rianiscool):
OpenStudy (unanimoose):
We already considered this one. :)
OpenStudy (anonymous):
8-12 = 4, 4*4/2=8 8+(8*4)=40
OpenStudy (rianiscool):
oh sorry one min wrong ons sorry
OpenStudy (anonymous):
12-8*
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OpenStudy (unanimoose):
It's fine. xD
OpenStudy (rianiscool):
What is the area of the shaded part of the figure?
A.
324 mm²
B.
243 mm²
C.
162 mm²
D.
81 mm²
OpenStudy (rianiscool):
OpenStudy (anonymous):
324-81
OpenStudy (unanimoose):
Ok, do you know how to find the area of a triangle?
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OpenStudy (anonymous):
which is 263
OpenStudy (anonymous):
no sorry not 263
OpenStudy (anonymous):
243
OpenStudy (unanimoose):
Ok well.
\[A = \frac { hb }{ 2 }\]
OpenStudy (anonymous):
the area of the triangle is base times height divided by 2
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OpenStudy (anonymous):
yea what he has, he will explain it
OpenStudy (anonymous):
bye
OpenStudy (unanimoose):
And then we know that it is a perfect square inside so :
\[A of Square = lw ~ or ~ 9^2\]
OpenStudy (rianiscool):
is the answer 162
OpenStudy (unanimoose):
That is the area of the triangle itself. We must also subtract the area of the square since it is not included in the shaded area.
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OpenStudy (unanimoose):
So: \[A = 162 - 9^2\]
OpenStudy (unanimoose):
It is \[9^2\] because it is a perfect square.
OpenStudy (rianiscool):
so 81
OpenStudy (unanimoose):
Yup!
OpenStudy (rianiscool):
ok thanks
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OpenStudy (unanimoose):
Np :)