2. A pencil cup is made of plastic It is 10 centimeters tall and has a radius of 25 centimeters. How many square centimeters of plastic were used to make the cup?
a Formula
b. Computation
c. Surface Area
3. The roof of a building in the form of a square pyramid has a slant height of 12 meters and a house base measuring 15 meters on a side. Find the surface area of the roof
a Fomula
b. Computation
c. Surface Area:
4. Find how many square decimeters of cardboard is needed to make a cubical soda cracker box measuring 5.6 decimeters on each edge?
a Formula
b. Computation
c. Surface Area
5. A cone shaped hat has a diameter of 30 centimeters and a slant height of 33 centimeters. What is the surface area of the hat?
a. Formula:
b. Computation:
c. Surface Area;
a Formula
b. Computation
c. Surface Area
3. The roof of a building in the form of a square pyramid has a slant height of 12 meters and a house base measuring 15 meters on a side. Find the surface area of the roof
a Fomula
b. Computation
c. Surface Area:
4. Find how many square decimeters of cardboard is needed to make a cubical soda cracker box measuring 5.6 decimeters on each edge?
a Formula
b. Computation
c. Surface Area
5. A cone shaped hat has a diameter of 30 centimeters and a slant height of 33 centimeters. What is the surface area of the hat?
a. Formula:
b. Computation:
c. Surface Area;
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Answer:
3. When you ask for the surface area of the given square pyramid, I’m not sure whether you’re asking for the total surface area or the lateral surface area, so I’ll calculate both.
We are given a square pyramid or, in other words, a regular pyramid with a square base each side which is 10 meters long. The pyramid has a slant height of 13 meters, a height of 12 meters, and, since the pyramid is regular, it has four (4) congruent triangular lateral faces.
The lateral surface area L of the given square pyramid is equal to the sum of the areas of all four triangular lateral faces each of which has a base b of 10 meters, which is the length of one side of the square base, and a height h of 13 meters (the slant height); therefore, the lateral surface area L is calculated as follows:
L = 4[(1/2)(base)(height)] = 4[(1/2)bh]
= 4[(1/2)(10 m)(13 m)]
= 4[(1/2)(130) square meters]
= 4(65) m²
L = 260 m²
The total surface area S of the square pyramid = B + L, where B is the area of the square base. Since each side of the square base is 10 meters in length, the area of the base is:
B = (length of one side)² = s²
= (10 m)²
= 100 m² Therefore, …
S = B + L
= 100 m² + 260 m²
S = 360 m²