Surface Area

Surface Area Surface area is found by finding the area of all the sides and then adding those answers up. How will the answer be labeled? Units2 because it is area!

Rectangular Prism B C A 5 in 6 4 How many faces are on here? 6 Find the area of each of the faces. Do any of the faces have the same area? A = 5 x 4 = 20 x 2 =40 If so, which ones? B = 6 x 4= 24 x 2 = 48 C = 5x 6 = 30 x 2 = 60 Opposite faces are the same. 148 in2 Find the SA

Cube Are all the faces the same? YES A How many faces are there? 4m 6 Find the Surface area of one of the faces. 4 x 4 = 16 Take that times the number of faces. X 6 96 m2 SA for a cube.

Triangular Prism x 2= 12 How many faces are there? 4 5 5 How many of each shape does it take to make this prism? 10 m 3 2 triangles and 3 rectangles = SA of a triangular prism Find the surface area. Start by finding the area of the triangle. x 2= 12 4 x 3/2 = 6 How many triangles were there? 5 x 10 = 50 = front 4 x 10 = 40 = back 3 x 10 = 30 = bottom 2 Find the area of the 3 rectangles. SA = 132 m2 What is the final SA?

Lateral area vs Area of the bases Lateral area is the area around a solid. Area of the bases are on the top and bottom.

Pyramids The top of a pyramid is called the apex

Pyramids Classification Square based There are many types of Pyramids, and they are named after the shape of their base.

Pyramids Triangular based pyramids Pentagonal based pyramids

Area formula  

Example   9cm 8cm 2cm 7cm

Cylinders SA = Areas bases + Lateral area SA = 2(Area base) + (perimeter of top)* height SA = 2(∏ R 2) + (2 ∏R)* h

Example   15 cm 3 cm

Cones SA= Area base + Lateral area SA = πr2 + π r l Slant height

Example   6cm 4cm 2cm

Working backwards   ? 3cm 10cm

Work SA= 2(rectangle 1)+ 2( rectangle 2) +2( rectangle 3) Plug in what you know: 500= 2( 10Xh) +2( 3xh) +2(3x10) 500=20h +6h +60 500=26h+60 500-60=26h 440=26h 16.92=h