Triangle ABC was dilated using the rule Y, 5/4. FCA is equal to eight what is C’A’ 10 units 12 and 16 units 20 units

C'A' = 10units (A)

Question

A complete question related to this found at (question ID 2475535) is stated below.

Triangle ABC was dilated using the rule Dy, 5/4

If CA = 8, what is C'A'?

10 units

12 units

16 units

20 units

Step-by-step explanation:

Given:

Scale factor = 5/4

CA = 8units

Find attached the diagram for the question.

This is a question on dilation. In dilation, figures have the same shapes but different sizes.

Y is the center of dilation

Lengths of ∆ABC: CB, AB, CA

Lengths of ∆A'B'C': C'B', A'B', C'A'

C'B' = scale factor × CB

A'B' = scale factor × AB

C'A' = scale factor × CA

C'A' = 5/4 × 8

C'A' = 40/4

C'A' = 10units (A)

there are lots of ways.   pick's theorem tells us if the vertices are lattice points the area a is

a = b/2 + i - 1

where b is the number of boundary lattice points and i is the number of interior lattice points.

in the figure i count b=16, i=50 so

a = 8 + 50 - 1 = 57

let's try the shoelace formula.   the area is half the sum of the cross products of the sides.  

a(-2,6)   -2(2)-6(-5) = 26

b(-5,2)   -5(-3) - 2(-2) = 19

c(-2,-3) -2(-3) - (-3)(4) = 18

d(4,-3)   4(3) - (-3)(5) = 27

e(5,3)   5(3) - 3(1) = 12

f(1,3)     1(6) - 3(-2) = 12

a(-2,6)

each of the cross products is twice the area of the triangle with the associated side and one vertex the origin. so the area of abo=26/2=13.

area = (1/2) (26 + 19 +   18 + 27 + 12 + 12) = 57

that checks!