Call the length L and there width W. then perimeter is 2L+2W=18. area is LW=20.
2L+2W=18
L+W=9
LW=20
L=9-W
(9-W)W=20
W²-9W+20=0
(W-5)(W-4)=0
W=4,5
rectangle is 4by5
The area of the triangle = 1/2 * base * altitude = 1.2 * 20 * a = 10a
Work out the altitude (a):-
the altitude forms a right angled triangle with vertex angle = 1/2*108 = 54
so tan 54 = 10 / a
a = 10 / tan 54 = 7.265
area of the triangle = 10 * 7.265 = 72.65 cm^2
For #6 + #8 You just have to double the radius to get the diameter. So you add 6 cm and 6cm to 12cm and you know 8 because it is the same process just not a whole number.
10 is easier than it looks because the formula for the circumference is 2 times pie times the radius or simpler is the diameter times pie. So you times 7 by 2 and then pie which will give you 43.96
Answer:
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