Odpowiedź:
z.2
π r² = 64 π / : π
r² = 64
r = 8 [ cm]
============
L =2π*r =2 π*8 = 16 π [ cm ]
z.3
a) π r² = [tex]\frac{1}{4}[/tex] π cm² / : π
r² = [tex]\frac{1}{4}[/tex] cm²
r = [tex]\frac{1}{2}[/tex] cm
===========
b) π r² = π cm² / : π
r² = 1 cm²
r = 1 cm
==========
c) π r² = 16 π cm² / : π
r² = 16 cm²
r = 4 cm
============
d) π r² = 4π cm² / : π
r² = 4 cm²
r = 2 cm
============
z.4
a) L = 6 π cm = 2π*r cm / : 2π
r = 3 cm
P = π*( 3 cm)² = 9 π cm²
==========================
b) L = 4√3 π cm = 2π* r cm /: 2π
r = 2√3 cm
P = π*( 2√3 cm)² = 12 π cm²
===========================
c) L = √12 π cm = 2π r cm
√4*√3 π cm = 2π r cm
2√3 π cm = 2π r cm / : 2π
r = √3 cm
P = π*(√3 cm)² = 3 π cm²
===================
d) L = √8 π cm = 2π r cm
√4*√2 π cm = 2π r cm
2√2 π cm = 2π r cm / : 2π
r = √2 cm
P = π*(√2 cm )² = 2π cm²
====================
Szczegółowe wyjaśnienie:
