1) tentukan -nilai r=sr -panjang AC -panjang BC 2) tentukan -nilai x - panjang DE - panjang DF

[tex] ab= \sqrt{(3r) {}^{2} + (4r) ^{2} } [/tex]
[tex] {20}^{2} = \sqrt{ {9r}^{2} + {16r}^{2} } [/tex]
[tex]400 = {25r}^{2} [/tex]
[tex]r = \sqrt{16} [/tex]
[tex]r = 4[/tex]
AC = 3xr = 3x4 = 12cm
BC = 4xr = 4x4 = 16cm


[tex] 2. \\ de = \sqrt{(x + 1) ^{2} } + {(12)}^{2} [/tex]
[tex] {(x + 7)}^{2} = \sqrt{ {x}^{2} + 2x + 1 + 144 } [/tex]
[tex] {x}^{2} + 14x + 49 = {x}^{2} + 2x + 145 [/tex]
12x = 96
[tex]x = \frac{96}{12} = 8[/tex]
DE = x + 7 = 8+7 = 15
DF = x + 1 = 8+1 = 9