tolong dibantu no 4&5

4. Garis singgung AB =
[tex] \sqrt{ {ob}^{2} - {oa}^{2} } \\ = \sqrt{ {30}^{2} - {18}^{2} } \\ = \sqrt{900 - 324} \\ = \sqrt{576} \\ = 24 \: cm[/tex]


5.
[tex]k = a + b + c \\ = 13 + 12 + 5 \\ = 30 \: cm \\ s = \frac{1}{2}k \\ = \frac{1}{2} \times 30 \\ = 15 \: cm \\ l = \frac{1}{2} \times a \times t \\ = \frac{1}{2} \times 5 \times 12 \\ = 5 \times 6 \\ = 30 \: cm \\ r = \frac{a \times b \times c}{4 \times l} \\ = \frac{13 \times 12 \times 5}{4 \times 30} \\ = \frac{780}{120 } \\ = 6.5 \: cm[/tex]
Atau dengan cara mudah = hipotenusa (sisi miring/sisi paling panjang) dibagi 2
= 13 ÷ 2 = 6.5 cm