SA Basics & Units
What does “surface area” mean?
The total area of all the outside faces of a 3D object.
Rectangular prism 8 cm × 5 cm × 3 cm. Find SA.
2(lw+lh+wh)=2(40+24+15)=158 cm²
A cube has side length 6 cm. Find SA.
6s2=6(36)=216 cm²
A triangular prism has 2 triangle faces and how many rectangular faces?
3
A rectangular prism net has 6 rectangles. True or False?
True
What units do we use for surface area?
Square units (cm², m², etc.).60 cm²
Rectangular prism 10 cm × 4 cm × 2 cm. Find SA.
2(40+20+8)=1362(40+20+8)=1362(40+20+8)=136 cm²
Rectangular prism: 4×4×10. Find surface area.
192 cm²
Triangle base: b=10 cm, h=6 cm. Find area of ONE triangle face.
30 cm²
A net shows 2 rectangles of area 40 cm² and 4 rectangles of area 15 cm². Find SA.
2×40+4×15=80+60=140 cm²
True or False: Surface area includes the space inside the solid.Triangle area is 36 cm² and base is 12 cm. Find the height.
False
Rectangular prism 12 cm × 7 cm × 2 cm. Find SA.
2(84+24+14)=244 cm²60 cm²
Cube with side length 6 cm. Find surface area.
216 cm²
Prism length is 12 cm. One triangle side is 8 cm. Area of the rectangle made from that side?
96 cm² (8×12)
A net shows rectangles with areas: 24, 24, 15, 15, 40, 40 (cm²). Find SA.
24+24+15+15+40+40=158 cm²
A rectangular prism has 6 faces. How many pairs of congruent faces does it have?Trapezoid area is 84 cm². Parallel sides are 9 cm and 15 cm. Find the height.
3 pairs
Rectangular prism 9 cm × 6 cm × 5 cm. Find SA.
2(54+45+30)=258 cm²
Rectangular prism: 12×7×2. Find surface area.
244 cm²
Triangular prism: triangle sides 10, 8, 8 cm; prism length 12 cm; triangle area is 30 cm². Find total surface area.
372 cm² (2 triangles = 60; rectangles = (10+8+8)×12 = 312; total 372)
A cereal box is 30 cm tall, 18 cm wide, 6 cm deep. Find SA.
2(30×18+30×6+18×6)=2(540+180+108)=1656 cm²
Circle one: Surface area is measured in (cm / cm² / cm³).
cm².
Rectangular prism 15 cm × 8 cm × 3 cm. Find SA.
2(120+45+24)=378 cm²
SA = 94 cm², length 6 cm, width 3 cm. Find the height.
29/9 cm (≈ 3.22 cm)
Triangle area is 24 cm² (one triangle). Triangle sides are 7, 8, 9 cm. Prism length 11 cm. Find SA.
A: Triangles: 2×24=482×24=482×24=48;
Rectangles: (7+8+9)×11=264(7+8+9)×11=264(7+8+9)×11=264;
Total =312=312=312 cm²
A box has SA 94 cm², length 6 cm, width 3 cm. Find height.
94=2(18+6h+3h)⇒47=18+9h⇒29=9h⇒h=29/9≈3.22 cm