Answer:
Right Angles: C, F
Obtuse Angles: E, B
Acute Angles: A, D
Step-by-step explanation:
Right Angles are angles that are exactly 90 degrees.
Obtuse Angles are angles that are bigger than 90 degrees.
Acute Angles are angles that are smaller than 90 degrees.
A pyramid is regular if its base is a regular polygon, that is a polygon with equal sides and angle measures.
(and the lateral edges of the pyramid are also equal to each other)
Thus a regular rectangular pyramid is a regular pyramid with a square base, of side length say
x.
The lateral faces are equilateral triangles of side length
x.
The lateral surface area is 72 cm^2, thus the area of one face is 72/4=36/2=18 cm^2.
now we need to find
x. Consider the picture attached, showing one lateral face of the pyramid.
by the Pythagorean theorem:
![h= \sqrt{ x^{2} - (x/2)^{2}}= \sqrt{ x^{2}- x^{2}/4}= \sqrt{3x^2/4}= \frac{ \sqrt{3} }{2}x](https://tex.z-dn.net/?f=h%3D%20%5Csqrt%7B%20x%5E%7B2%7D%20-%20%28x%2F2%29%5E%7B2%7D%7D%3D%20%5Csqrt%7B%20x%5E%7B2%7D-%20x%5E%7B2%7D%2F4%7D%3D%20%5Csqrt%7B3x%5E2%2F4%7D%3D%20%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B2%7Dx%20%20%20%20)
thus,
![Area_{triangle}= \frac{1}{2}\cdot base \cdot height\\\\18= \frac{1}{2}\cdot x \cdot \frac{ \sqrt{3} }{2}x\\\\ \frac{18 \cdot 4}{ \sqrt{3}}=x^2](https://tex.z-dn.net/?f=Area_%7Btriangle%7D%3D%20%5Cfrac%7B1%7D%7B2%7D%5Ccdot%20base%20%5Ccdot%20height%5C%5C%5C%5C18%3D%20%5Cfrac%7B1%7D%7B2%7D%5Ccdot%20x%20%5Ccdot%20%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B2%7Dx%5C%5C%5C%5C%20%5Cfrac%7B18%20%5Ccdot%204%7D%7B%20%5Csqrt%7B3%7D%7D%3Dx%5E2%20)
thus:
![x^2 =\frac{18 \cdot 4}{ \sqrt{3}}= \frac{18 \cdot 4 \cdot\ \sqrt{3} }{3}=24 \sqrt{3}](https://tex.z-dn.net/?f=x%5E2%20%3D%5Cfrac%7B18%20%5Ccdot%204%7D%7B%20%5Csqrt%7B3%7D%7D%3D%20%5Cfrac%7B18%20%5Ccdot%204%20%5Ccdot%5C%20%20%5Csqrt%7B3%7D%20%7D%7B3%7D%3D24%20%5Csqrt%7B3%7D%20%20)
(cm^2)
but
![x^{2}](https://tex.z-dn.net/?f=%20x%5E%7B2%7D%20)
is exactly the base area, since the base is a square of sidelength =
x cm.
So, the total surface area = base area + lateral area =
![24 \sqrt{3}+72](https://tex.z-dn.net/?f=24%20%5Csqrt%7B3%7D%2B72)
cm^2
Answer:
![24 \sqrt{3}+72](https://tex.z-dn.net/?f=24%20%5Csqrt%7B3%7D%2B72)
cm^2
Answer:
D. is correct!
Step-by-step explanation:
ht tps://us-static.z-dn.net/fil es/ded/302e17a93f9f7dceb0b9635c302342ae.jp g
^ just an example
brainliest?
Answer:
Ok then send the drawing
Step-by-step explanation: