Plz can u help rn please I need it

Mathematics

2 answers:

goblinko [34]2 years ago

8 0

See photo fro solution

alexdok [17]2 years ago

5 0

416.68 cm #your wlcome

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a regular rectangular pyramid has a base and lateral faces that are congruent equilateral triangles. it has a lateral surface ar

Margarita [4]

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:

$h= \sqrt{ x^{2} - (x/2)^{2}}= \sqrt{ x^{2}- x^{2}/4}= \sqrt{3x^2/4}= \frac{ \sqrt{3} }{2}x$

thus,

$Area_{triangle}= \frac{1}{2}\cdot base \cdot height\\\\18= \frac{1}{2}\cdot x \cdot \frac{ \sqrt{3} }{2}x\\\\ \frac{18 \cdot 4}{ \sqrt{3}}=x^2$

thus:

$x^2 =\frac{18 \cdot 4}{ \sqrt{3}}= \frac{18 \cdot 4 \cdot\ \sqrt{3} }{3}=24 \sqrt{3}$ (cm^2)

but $x^{2}$ is exactly the base area, since the base is a square of sidelength = x cm.

So, the total surface area = base area + lateral area = $24 \sqrt{3}+72$ cm^2

Answer: $24 \sqrt{3}+72$ cm^2

4 0

2 years ago

16.8 - (-23.72)+(-31.3) = x

KatRina [158]

Let's solve your equation step-by-step

16.8-(-23.72)-31.3=x

Step 1:simplify both sides of the equation

16.8-(-23.72)-31.3=x

16.8+23.72+-31.3=x

(16.8+23.72+-31.3)=x (combine like terms)

9.22=x

Step 2: flip the equation

Answer: x=9.22

5 0

2 years ago

Paul and Charlene are 420 miles apart. They start toward each other with Paul driving 16 mph faster than Charlene. They meet in

Thepotemich [5.8K]

Answer:

34 mph.

Step-by-step explanation:

Let x be speed of Charlene, then speed of Paul will be x+16 as we are given that Paul is driving 16 mph faster than Charlene.

Let y be distance covered by Charlene, then distance covered by Paul will be 420-y.

Now we will use formula $\text{Speed}=\frac{\text{Distance}}{\text{Time}}$ . Upon using our given information we will get two equation and two unknowns as: