length AB: 1u

2u + base = 32


4u + base + 2xshort = 60

2u + 32 + 2short = 60
1u + short = 14
short = 14-1u

short = base - 1u

14-1u = base - 1u
base = 14

1u = (32-14)/2 = 9

AB = 9 cm

.
.
.

Non-algebra method :

①The equal sides of an isosceles triangle are called legs. The third side is called the base.

②Figure 2's perimeter consists of 4 legs + 1 base + 2 shorter sides.

But we can see that 1 shorter side + 1 leg make up 1 base.

So if we transfer a leg and join it to a shorter side, we get a base. Since there are 2 shorter sides, we transfer 2 legs.

Now the perimeter can be said to be equal to 2 legs + 1 base + 2 bases
= 2 legs + 3 bases

This equals 60cm.


③From figure 1 we know that 2 legs and 1 base = 32cm

So the difference between Figure 1 and 2 is just 60cm - 32cm = 28cm


The difference is also equal to length of 2 bases , so length of 2 bases = 28cm

1 base equals 28cm ÷ 2 = 14cm

④ Length of 2 legs

= 32cm - 14cm
= 18cm

Length of 1 leg
= 18cm ÷ 2
= 9cm