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2 years ago

Can someone check my answers

Mathematics

1 answer:

omeli [17]2 years ago

8 0

I'm pretty sure that's correct :).

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A square pyramid has base area 64 square centimeters. The surface area of this pyramid is 224 square centimeters. Find the heigh

dolphi86 [110]

Answer:

$h \approx 12.7\,cm$

Step-by-step explanation:

The side of the square base is:

$l = \sqrt{64\,cm^{2}}$

$l = 8\,cm$

The formula for the surface area of the pyramid is:

$A_{s} = \frac{1}{2}\cdot (3\cdot l)\cdot \sqrt{0.25\cdot l^{2}+h^{2}} + l^{2}$

The height is cleared in the previous expression:

$A_{s} - l^{2} = \frac{3}{2}\cdot l\cdot \sqrt{0.25\cdot l^{2}+h^{2}}$

$\frac{2}{3}\cdot \frac{A_{s}-l^{2}}{l} = \sqrt{0.25\cdot l^{2} + h^{2}}$

$\frac{4}{9}\cdot \left(\frac{A_{s}-l^{2}}{l} \right)^{2} = \frac{1}{4} \cdot l^{2} + h^{2}$

$h = \sqrt{\frac{4}{9}\cdot \left(\frac{A_{s}-l^{2}}{l} \right)^{2} - \frac{1}{4}\cdot l^{2}}$

$h = \sqrt{\frac{4}{9}\cdot \left[\frac{224\,cm^{2}-(8\,cm)^{2}}{8\,cm}\right]^{2}-\frac{1}{4}\cdot (8\,cm)^{2} }$

$h \approx 12.7\,cm$

6 0

2 years ago

Solve the system of equations.<br> 2x+8y=6<br> -5x-20y+-15

kondor19780726 [428]

Answer:

2x+8y=6

Step 1: Add -8y to both sides.

2x+8y+−8y=6+−8y

2x=−8y+6

Step 2: Divide both sides by 2

$\frac{2x}{2}$ = $\frac{-8y+6}{2}$

x=−4y+3

_________________________________________________________

−5x−20y−15

There are no like terms.

Answer:

=−5x−20y−15

7 0

2 years ago

The given amount converted to units?

Alisiya [41]

120 seconds is 2 * 60s
60s is 1 minute, so 2*60s = 2 minutes

4 0

2 years ago

8/2z=15/60 .solve proportion.

masya89 [10]

$\frac{8}{2z}=\frac{15}{60}\ \ \ \ \ |cross\ multiply\\\\2z\cdot15=8\cdot60\\\\30z=480\ \ \ \ |divide\ both\ sides\ by\ 30\\\\\boxed{z=16}$

8 0

2 years ago

Read 2 more answers

How do i solve this?

Natalija [7]

Because you know the area and that the shape is a square... if the side length is "s"... to find "s" you would say...

s²=1.69

Take the root of both sides and...

s=1.3 km

8 0

2 years ago