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zalisa [80]
2 years ago
8

A regular triangular pyramid has a base and lateral faces that are congruent equilateral triangles. It has a lateral surface are

a of 81 square feet. What is the surface area of the regular triangular pyramid?
Mathematics
1 answer:
TEA [102]2 years ago
4 0
We know that

[lateral surface area of a regular triangular pyramid]=3*[area of one <span>equilateral triangle]
so
[area of one </span>equilateral triangle]=lateral surface/3-----> 81/3-----> 27 ft²

[<span>surface area of the regular triangular pyramid]=lateral area+area of the base

area of the base is equals to the area of the lateral sides because are </span>equilateral triangles

therefore
area of the base=27 ft²

[surface area of the regular triangular pyramid]=81+27----> 108 ft²

the answer is
<span>the surface area of the regular triangular pyramid is 108 ft</span>²
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Answer:

B.254.34 in.2

Step-by-step explanation:

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3 years ago
Nathan ordered one cheeseburger and one bag of chips for 3.75 jack ordered two cheeseburgers and three bags of chips for 8.25 kn
Elan Coil [88]

Answer:

cheeseburger is $3 and chips is $0.75

Step-by-step explanation:

Let price of cheeseburger be x while price of a bag of chips be y hence for the case of Nathan, we can write the equation as x+y=3.75. Similarly, for Jack, we can write it as 2x+3y=8.25

x+y=3.75 hence x=3.75-y and substituting this into the second equation we have

2x+3y=8.25

2(3.75-y)+3y=8.25

7.5-2y+3y=8.25

y=8.25-7.5=0.75

x=3.75-y=3.75-0.75=3

Therefore, price of cheeseburger is $3 and chips is $0.75

7 0
3 years ago
Rewrite each expression as a polynomial in standard form.a)(x+i)(x-i)b)(x+5i)(x-5i)
Nitella [24]

Answer:

a) x² +1

b) x² +25

Step-by-step explanation:

a) (x+i)(x− i)

   = x² - ( i ) x + ( i ) x - ( i)²

   = x² -  i²                       ∵ i² = -1

   = x² -  (-1)

   = x² +1

b) (x+5 i)(x− 5i)

 = x² - ( 5 i ) x + ( 5 i ) x - ( 5 i)²

   = x² - 25 i²                       ∵ i² = -1

   = x² -  25(-1)

   = x² +25

we can also solve

using identity

   (a + b)(a - b) = a² - b²

   = (x+5 i)(x− 5i)    

   = x² - (5 i)²

   = x² - 25 i²

   = x² +25

8 0
3 years ago
You can spend at most $20 on tomatoes and red peppers for a soup. Tomatoes cost $2.50 per pound and red peppers cost $4 per poun
Umnica [9.8K]

Answer:

The expression which represents the quantity of tomatoes and red peppers to buy is $ 2.50 × T + $ 4 × R = $ 20

Step-by-step explanation:

Given as :

The total amount spend for soup = $ 20

The cost of Tomatoes = $ 2.50 per pound

The cost of Red peppers = $ 4 per pound

Let the quantity of tomatoes to be bought = T pound

The quantity of red peppers to be bought = R pound

So, According to question

$ 2.50 × T + $ 4 × R = $ 20

I.e The expression which represents the quantity of tomatoes and red peppers to buy is $ 2.50 × T + $ 4 × R = $ 20   . Answer

5 0
3 years ago
Evaluate (6.1 x 10-3) (8 x 109). Write your answer in scientific notation and standard form.
DerKrebs [107]

Answer:

Scientific Notation: 4.88 ×10^7

Standard Form: 4.88 ×10^7

Step-by-step explanation:

6.1×10^(-3) = 0.0061

8×10^9 = 8000000000

0.0061×8000000000 = 48800000

= 4.88 \times  {10}^{7}

3 0
2 years ago
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