Answer:
20
Step-by-step explanation:
The factors of 20 are 1, 2, 4, 5, 10, and 20. The factors of 80 are 1, 2, 4, 5, 8, 10, 16, 20, 40, and 80. You can see that they have some of the same factors, but the greatest they share is 20
Given:
A square base pyramid with base length 6 cm and the slant height is 4 cm.
To find:
The lateral surface area of the given square pyramid.
Solution:
The lateral surface area of the given square pyramid is equal to the areas of 4 congruent triangles with base 6 cm and height 4 cm.
Area of a triangle is:
![Area=\dfrac{1}{2}\times base\times height](https://tex.z-dn.net/?f=Area%3D%5Cdfrac%7B1%7D%7B2%7D%5Ctimes%20base%5Ctimes%20height)
So, the area of one triangle or one side of the given pyramid is:
![A_1=\dfrac{1}{2}\times 6\times 4](https://tex.z-dn.net/?f=A_1%3D%5Cdfrac%7B1%7D%7B2%7D%5Ctimes%206%5Ctimes%204)
![A_1=\dfrac{24}{2}](https://tex.z-dn.net/?f=A_1%3D%5Cdfrac%7B24%7D%7B2%7D)
![A_1=12](https://tex.z-dn.net/?f=A_1%3D12)
Now, the lateral surface area of the given square pyramid is 4 times the area of one triangle.
![LA=4A_1](https://tex.z-dn.net/?f=LA%3D4A_1)
![LA=4(12)](https://tex.z-dn.net/?f=LA%3D4%2812%29)
![LA=48](https://tex.z-dn.net/?f=LA%3D48)
Therefore, the lateral surface area of the given square pyramid is 48 cm².
(a) The first answer is “A” because 480 / 8 is = 60
(b) a the answer is also “A” because 502 / 8 = 62.5, so it is a underestimate
Answer:
20 miles
Step-by-step explanation:
It is useful to remember that % means /100, and that 1% = 1/100.
Here, you want 1/2% × 4000. The associative property of multiplication lets you rearrange this to ...
(1/2)% × 4000 = (1/2) × 1% × 4000
= 1/2 × (1/100 × 4000) = 1/2 × 4000/100
= 1/2 × 40 = 20 . . . miles
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If you refuse to be intimidated by percentages, you can do this math in your head.