Tolong bantuannya, no 18-21. pakai cara

18.)r²=PQ²-QR²
=17²-15²
=289-225 = 64
r=√64 = 8 cm (B)

19.)d²=p²-(r2+r1)²
=20²-(8+4)²
=20²-12²
=400-144 = 256
d=√256 = 16 cm (B)

20.)l²=p²-(r2-r1)²
15²=p²-(12-4)²
15²=p²-8²
225+64=p²
289=p²
√289=p
17cm=p (C)

21.)l²=p²-(r1-r2)
24²=p²-(12-5)²
24²=p²-7²
576+49=p²
625=p²
√625=p
25cm =p (B)

Semoga membantu ^^