Constructions, Bearings, Loci & 3D Views

How do you calculate real distance using a scale drawing?

Real = Map * Scale Factor.

How do you calculate map distance using real distance and scale factor?

Map = Real / Scale Factor.

What is the 1st golden rule of measuring bearings?

Measure from NORTH.

What is the 2nd golden rule of measuring bearings?

Measure CLOCKWISE.

What is the 3rd golden rule of measuring bearings?

Write as 3 DIGITS (e.g., 045°).

How do you calculate a back bearing from a given bearing?

If < 180° add 180°; if > 180° subtract 180°.

How do you construct a perpendicular bisector of a line?

Draw intersecting arcs from endpoints; join intersections.

How do you construct an angle bisector?

Arc from vertex, then intersecting arcs from arms; join to vertex.

What locus is formed by points at a fixed distance from a point?

Circle around the point.

What locus is formed by points at a fixed distance from a straight line?

Parallel lines with semi-circular ends.

What locus is formed by points equidistant from two given points?

Perpendicular bisector.

What locus is formed by points equidistant from two intersecting lines?

Angle bisector.

How do you solve loci region problems?

Construct boundaries and shade overlapping region.

What is a plan view of a 3D shape?

2D view looking DOWN from above.

What is a front elevation of a 3D shape?

2D view looking straight at FRONT.

What is a side elevation of a 3D shape?

2D view looking straight at SIDE.