The ratio of the height (h) of the streetlight to its distance to the end of Laura's shadow is the same as the ratio of Laura's height to her distance from the end of her shadow.
.. h/(12+9) = 5'4"/9
.. h = (21/9)*5'4" = 12 4/9 feet
.. h = 12 ft 5 1/3 inches
The streetlight is 12 ft 5 1/3 inches tall.
The lateral area would be 298.7 cm².
The lateral area is the area of all of the lateral faces of the pyramid. There are 8 triangles making up the lateral faces. Each has a base of 6.6. The formula for the area of a triangle is
A=1/2bh,
so we still need the height of the triangle.
The height of each lateral triangle is the slant height of the pyramid. The slant height of the pyramid forms a right triangle with the height of the pyramid and the "radius" as it were of the pyramid. Thus we use the Pythagorean theorem:
8²+8²=h²
64+64=h²
128=h²
√128=√(h²)
8√2 = h
Substituting this into our area formula we have:
A=1/2(6.6)(8√2)
We will go ahead and multiply this by 8, since there are 8 lateral faces:
LA=8(1/2)(6.6)(8√2)
LA = 298.7
An other name is skip counting
It's D if you need an explanation let me know