1. the diagram shows 5 ft student standing near a tree. the shadow of the student and the shadow of the tree end at point a. what is the height of the tree? show all your work, and make sure to include units in your final answer.

Using similiar triangles set up the ratio of proportion:

E,F / A,F = B,C/A,C

5 / 8 = BC / 40

Cross multiply:

(5 *40) = (8* BC)

200 = 8BC

Divide both sides by 8

BC = 200/8

BC = 25 feet

Step-by-step explanation:

the idea is ratio and proportion:

 5 ft.   =     x ft.    

 8 ft.          40 ft.

cross multiply:    8 (x) = 40 (5)

simplify:                   x = 200 / 8

answer :                  x = 25 ft.

therefore, the height of the tree is 25 ft.

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb