Answer:
a) 7/4 b) 15/2
Explanation:
a) Scale Factor = Image / Object
Take the side of Triangle ABC that's BC Why? Because it corresponds with the Image Triangle ADE's DE
= 21/12 = 7/4
b) 7/4 = 10+ x / 10
Cross Multiply
= 4 ( 10 + x ) = 70
= 40 + 4x = 70
= 4x = 70-40
= 4x = 30
= 4x/4 = 30/4
x = 15/2