Question

Can some one help me, l forgot how to do it

Answer 1

48 cm² and 28 cm

Explanation:

The ratio of the sides 1 : 2 = 4 : 7

The ratio of the sides 2 : 1 = 7 : 4

The ratio of perimeters is the same as ratio of sides

let the perimeter of 2 be x , then

`(16)/(x)` =
`(4)/(7)` ( cross- multiply )

4x = 112 ( divide both sides by 4 )

x = 28

Perimeter of fig. 2 is 28 cm

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Given ratio of sides = a : b , then

ratio of areas = a² : b²

Here ratio of sides = 4 : 7

ratio of areas = 4² : 7² = 16 : 49

let x be the area of fig. 1 and using proportion

`(16)/(x)` =
`(49)/(147)` ( cross- multiply )

49x = 2352 ( divide both sides by 49 )

x = 48

area of fig. 1 is 48 cm²

Answer 2

Area of Figure 1 = 48

Explanation:

We are given CD and EF. We can use this to find the scale factor between the two shapes.

The scale factor from Figure 1 to Figure 2 is 7/4.

The scale factor from Figure 2 to Figure 1 is 4/7.

Perimeter of Figure 2: 16 × 7/4 = 28cm, which is correct.

Area of Figure 1: 147 × (4/7)^2 = 48cm^2 We square the SF as we only worked out the Length Scale Factor. The Area Scale Factor is the Length Scale Factor squared.

I hope this helps!! ^-^