Surface Area Flashcards

All 7 cards in this deck

True or false? Surface area is measured in cubic units such as cm$^3$.

False. Surface area is the total area of all the faces, so it is measured in square units such as cm$^2$.

What is the total surface area of a cube with edge length $x$?

$6x^2$

e.g. edge $5$ cm: $6 \times 5^2 = 150$ cm$^2$

What are the steps to find the total surface area of a cuboid?

e.g. a cuboid $6$ cm by $5$ cm by $3$ cm

1. Area of three different faces: $6 \times 5 = 30$, $6 \times 3 = 18$, $5 \times 3 = 15$
2. Add them: $30 + 18 + 15 = 63$
3. Double (faces come in pairs): $63 \times 2 = 126$ cm$^2$

What is the formula for the total surface area of a solid cylinder of radius $r$ and height $h$?

$2\pi r h + 2\pi r^2$

Curved surface plus the two circular ends.

What is the formula for the surface area of a sphere of radius $r$?

$4\pi r^2$

What are the steps to find the volume of a cube from its total surface area?

e.g. total surface area $150$ cm$^2$

1. Area of one face: $150 \div 6 = 25$
2. Side length: $\sqrt{25} = 5$
3. Volume: $5 \times 5 \times 5 = 125$ cm$^3$

True or false? Two cuboids with the same volume can have different surface areas.

True.
e.g. a $1$ cm by $1$ cm by $8$ cm cuboid and a $2$ cm cube both have volume $8$ cm$^3$ but their surface areas are $34$ cm$^2$ and $24$ cm$^2$.