Chapter 3 Flashcards
What 3 units are areas usually measured in?
Square feet, square yard or acres
1 AC = how many square feet?
43,560
How many square inches are in 1 square foot?
144 square inches
How many square feet are in 1 square yard?
9 square feet
What is Pi rounded for the sake of this test?
3.1416
What is the basic formula used for simple area computations?
Area = Length x Height (A=LxH)
How do you determine the area of a trapezoid using the two parallel sides?
Find the average of the two parallel sides. Add side 1 to side 2 then divide by 2. Area=(a+b/2)H
How do you convert square feet to square yards?
Divide by 9.
Typical triangles where the height is perpendicular to the base can be treated as one 1/2 of a rectangle or parallelogram. What equation is used?
A=BH/2
How do you find out how many square feet are in an amount totaled in square inches?
Divide the total by 144.
What is the equation used if you don’t know the height of a triangle but you know the length of all sides?
Area= Square Root of s(s-a)(s-b)(s-c)
S=0.5(a+b+c)
If an acre has 43,560 square feet, how many feet are in 2 and two-tenths acres?
95,832
In the case of a right triangle (where the one angle is 90 degrees) we can find the length of any side if we know the length of the other two sides. What equation is used?
c= square root of a squared + b squared
What does the diameter of a circle equal?
2 x the radius (r)
How do you determine the circumference of a circle?
circumference (c) = pi x Diameter (D)
What is the formula used to determine the area of a circle?
Circle Area = pi x r squared
What is the formula used to determine the area of a sector of a circle?
Area of Sector = pi x r squared x angle/360
What is a radian?
The ratio of the length of an arc of a circle to the length of the radius. It serves as the measurement of the central angle between two radii.
What is the formula used to determine the amount of radians in a sector?
Radians = Arc/Radius
What is the formula used to determine Centerline Length?
Centerline Length = (Sector Angle Degree) (Pi)(r) / 180
What is the formula for determining the Correction Factor when determining the survey line?
Correction Factor = Centerline Radius/Survey Line Radius
Suppose that 2 curves we need to measure, for a survey line inside the area and one outside the area, both have a centerline survey radii of 200 feet and the roadway had a 24 foot width. How do you determine the radii for the two curves?
Inside curve radius = 200’ -1/2 (24’) =188ft.
Outside curve radius= 200’ + 1/2 (24’) = 212ft.
What is the formula used to determine the roadway width by the curve correction factor?
Area = (Roadway Length) x (Width) x (Curve Correction Factor)
How do you find the inside curve radii?
Subtract the road width from the outside curve radii
What is the formula used to determine the area of an a ellipses?
A= Pi (R) (r)
What is the Latitude and Departure method?
A method of measurement utilizing offset points to calculate areas. The offset points are referenced to a surveyed baseline or centerline of construction.
How far apart are Stations?
100 ft.
How should field measurements be taken? And what should accompany odd areas?
Clearly on site source records. Sketches should accompany odd area records.
