Head First 2D Geometry

4 Chapter 1

assessing the crime scene

Do the angles between Benny, Micky,

and the bullet match up?

At the crime scene, the investigators took some measurements

and sketched the positions of Benny, Micky’s body, and the point

where they found the bullet in the wall, all relative to the building

where the crime took place.

They must have been busy that day, because

they didn’t measure everything! But, they

found one important detail: the bullet

entered the wall at an angle of 18º through

the front wall.

So, to solve the crime, all you have to do is

prove that from where Benny was standing

to the target (Micky), the bullet would have

traveled in a straight line that joins up

perfectly with the bullet path.

BULLET

PATH

DOOR

MICKY

BENNY

FOOTPRINTS

BULLET FOUND

STUCK IN WALL HERE

18º

CRIME SCENE SKETCH

CASE GEO180

(ANGLES AS MEASURED

BUT DRAWING NOT TO

SCALE)

81º

86º

BULLET

PATH

MICKY

BENNY

18º

The line Benny would

aim down to hit Micky.

How the bullet was

traveling when it

hit the wall.

PLAN VIEW

Top-down view of the

crime scene

(CHALK OUTLINE

OF HIS BODY)

If Benny shot Micky, these

two line segments must join up

to make a straight line.

you are here 4 5

finding missing angles

Well, this is easy! You can see just

by looking at it that the line from

Benny to Micky and the line for the bullet

path join up to make ...