I dont know sorry i am also bad in math
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
The answer is B because area it's length times width and 5 times 3 is 15
Answer:
The statement which is true in the choices is the third item in the choices such as "Nina makes 20x dollars at the clothing store each week". It was clearly stated in the given that x represent the total number of hours she worked in a week. This statement made the other items in the choices wrong.
Step-by-step explanation:
I hope this helps you :)
Answer:
Step-by-step explanation:
1. First you add like terms
12b+5.54b+2.46b-2b = 18b
3.2a+1.17a = 4.37a
2. Now you write it out
18b+4.37a
3. CELEBRATE!!!!
4. Pat yourself on the back one more problem done
5. Have a nice day
:)