Question

I don't understand 11a or b. Please help.

Answer 1

11a
HJ=HK
HJ=2JK
HJ=15=HK
15=2jk
7.5=jk
15+15+7.5=37.5=HJK
11b
HJ=4x
HK=3x
JK=2x
9x=63
x=7
HJ=4x
HJ=4(7)=28

Answer 2

11a

you need to work out the length of the 3 line segments and add them to find the perimeter
HJ = HK = 15
and JK = 1/2 * HJ = 1/2 * 15 = 7.5

Therefore perimeter = 15 + 15 + 75. = 37.5

11b
4x + 3x + 2x = 63
9x = 63
x = 7

so HJ = 4x = 4*7 = 28