Answer:
Total surface area of the pyramid = 
Step-by-step explanation:
To find the surface area of the triangular- based pyramid, we will use the formula:
Surface area = Area of base + Area of the three faces
Area of base of the pyramid = Area of equilateral triangle = 

Area of the slant faces of the pyramid is 

Since there are 3 slant surfaces the total surface area of the pyramid =
94.1224489795918367 is the answer to your question
Cosine is co added onto sine. Basically, cosine is the sine function moved over 90degrees or pi/2 (pi/2 on a unit circle is 90 degrees)
Sin(x)=cos(x+90) <--degrees
Sin(x)=cos(x+pi/2) <--radians
The above two equations for converting them is called a cofunction identity. There's many more identities to convert sines, cosines, tangents, cosecantes, secantes, and cotangents between each other. This is taught to you in PreCalculus.
(C) "serpentine"
Serpentine is a winding word. The phrase would read "The mountain road was distinctly serpentine: it twisted back and forth along the contours of the hillside" if this term were added to the text.
The comma denotes that the meaning of the omitted phrase will be clarified in the second clause of the sentence. Because a winding road does actually curve "back and forth," the word "serpentine" matches the text. The answer is not (A).
A panoramic view is one that encompasses the entire surrounding region. (B) is the wrong answer. Precipitous refers to a steep slope. The answer is not (D). The term "circumscribed" describes something that is restrained or encircled by a line. The answer is not (E). Moving backward is referred to as retrograding.
Here's another question with an answer similar to this about passage analysis: brainly.com/question/3521530
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Make a proportion 20 miles/4 hours= 75miles/x. cross multiply gives you 20x=300. this will give you x = 15 hours