Question

Tolong ya pakai cara .

Answer 1

A) Keliling = 2 x x r
= 2 x 22/7 x 21 cm
= 132 cm
Luas = x r x r
= 22/7 x 21 cm x 21 cm
= 1386 cm²

b) Keliling = 2 x x r
= 2 x 3,14 x 30 cm
= 188,4 cm
Luas = x r x r
= 3,14 x 30 cm x 30 cm
= 2826 cm²

c) Keliling = 2 x x r
= 2 x 22/7 x 49 cm
= 308 cm
Luas = x r x r
= 22/7 49 cm x 49 cm
= 7546 cm

d) Keliling = x d
=  3,14 x 12 cm
= 37,68 cm
Luas = x r x r
= 3,14 x (12 cm : 2) x (12 cm : 2)
= 3,14 x 6 cm x 6 cm
= 113,04 cm²

e) Keliling = x d
= 22/7 x 35 cm
= 110 cm
Luas = x r x r
= 22/7 x (35 cm : 2) x (35 cm : 2)
= 22/7 x 17, 5 cm x 17,5 cm
= 962,5 cm²

f) Keliling = x d
= 3,14 x 40 cm
= 125,6 cm
Luas = x r x r
= 3,14 x (40 cm : 2) x (40 cm : 2)
= 3,14 x 20 cm x 20 cm
= 1256 cm²

Answer 2

A. π x r² =
22/7 x 21 x21 =
22 x 3 x 21 = 1386 cm²

b. π x r² =
3,14 x 30 x30 =
314 x 3 x3 = 2826 cm²

c. π x r² =
22/7 x 49 x 49 =
22 x 7 x 49 = 7546 cm²

d. π x r²
3,14 x 6 x 6 = 113,04 cm²

e. π x r²
22/7 x 17,5 x 17,5 =
22 x 2,5 x 17,5 = 962,5 cm²

f. π x r² =
3,14 x 20 x 20 =
314 x 2 x 2 = 1256 cm²