Step-by-step explanation:
DG+GM=DM
r+2+2r-13=25
combine like terms
3r-11=25
3r=36
r=12
Answer:
loooooooool
Step-by-step explanation:
Let’s assume the point in the centre is the origin of the circle.
This means the radius is 21/2 = 10.5cm.
180 - 168 = 12 degrees as the angle between BC.
Circumference of a sector is:
Angle/360 • pi • diameter
=12/360 • pi • 21 cm
= 2.19 cm = 2.20 cm
Which is option B
The answer is A because there is a constant pattern
Answer: Choice C) 124 square cm
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Explanation:
Let's calculate the area of the trapezoid shown
b1 and b2 are the parallel bases; h is the height of the 2D trapezoid
b1 = 2
b2 = 5
h = 1.5
A = h*(b1+b2)/2
A = 1.5*(2+5)/2
A = 1.5*7/2
A = 10.5/2
A = 5.25
The area of one 2D trapezoid is 5.25 sq cm
There are two of these trapezoids that form the base faces of the trapezoidal prism. So the total base area is 2*5.25 = 10.5 sq cm
Keep this value (10.5) in mind. We'll use it later.
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Now onto the lateral surface area (LSA)
It turns out that the formula for the LSA is
LSA = p*d
where
p = perimeter of the trapezoid shown
d = depth or height of the 3D trapezoid (I'm not using h as it was used earlier)
This formula works for any polygonal base. It doesn't have to be a trapezoid.
In this case the perimeter is,
p = 1.7+2+2.65+5
p = 11.35
So
LSA = p*d
LSA = 11.35*10
LSA = 113.5
Add this LSA to the base area found earlier
10.5+113.5 = 124
The total surface area is 124 square cm
