lesson #28 - surface area of prisms
DESCRIPTION
A=pr2 A=bh 2 =p(6cm)2 =36p cm2 =(4m)(3m) 2 =113.1 cm2 =6 m2 5 m 4 m 1) Area of a Circle Area of a Triangle 3 m 4 m 5 m 6 cm A=pr2 A=bh 2 =p(6cm)2 =36p cm2 =(4m)(3m) 2 =113.1 cm2 =6 m2TRANSCRIPT
Lesson #28 - Surface Area of Prisms
1) Area of a Circle
6 cm
A=r2
=(6cm)2
Area of a Triangle
3 m
4 m5 m
A=bh 2 =(4m)(3m) 2 =6 m2
=36 cm2
=113.1 cm2
Area of a Polygon
A=apothem(P) 2
=60 mm2
3 cm
4 cm
2 cm
Area of a Trapezoid
=(5mm)(6)(4mm) 2
4 mm
5 mm
A=(b1+b2)(h) 2 =(2cm+4cm)(3cm) 2
=9 cm2
2) TSA of a Cube
A=6s2
=6(3cm)2
A=54 cm2
3 cm
3) TSA of a prism
5 cm
21 cm
€
[1] Find the triangle h
a2 = c 2 −b2
a2 = (5cm)2 − (2.5cm)2
a2 =18.75cm2
a ≈ 4.33 cm
€
[2] Find the triangle area
A = bh2
= (5cm)(4.33cm)2
=10.825cm2
€
[3] Find the TSAAT = 2ABase + ALATAT = 2ABase + P(h)
= 21.65cm2 + (15cm)(21cm)
= 336.65 cm2
r=5 cm
h=10 cm
4) TSA of a cylinder
10 cm
5 cm
€
Find the TSAAT = 2ABase + ALATAT = 2πr2 + 2πrh
= 2π (5cm)2 + 2π (5cm)(10cm)
=150π cm2
≈ 471.2 cm2
The cylinder is 150π cm2
Homework
Pg. 178 #3-5Pg. 179 #6,8 & 12Pg. 181 # 14ab,15