7th Grade Pre-Algebra: Help with Area and Volume
By the end of 7th grade, you'll have learned to calculate area for most 2-dimensional shapes, as well as surface area and volume for regular 3-dimensional shapes. Keep reading for information about the relevant formulas.
Area and Volume for 7th Graders
Students usually learn about area and volume in geometry class, but these can also be considered pre-algebra skills because they require you to solve for a variable. For instance, if you're finding the area of a rectangle, you'll solve the equation A = length x width for the variable 'A.' Alternatively, you might be asked to solve for the rectangle's length when given its area and its width.
Area and Surface Area
Many 7th graders have already learned the area formulas for most 2-dimensional shapes, but some schools introduce the formula for the area of a circle in 7th grade. The formula is A = (pi)r^2, where 'r' is the radius (half the diameter), and the value of 'pi' is 3.14.
The surface area for any regular, 3-dimensional object, like a cylinder or rectangular prism, is equal to the sum of the areas of its surfaces. For instance, a rectangular prism has two smaller bases and four larger sides. To find the total surface area, add together the areas of the two small bases. Then, add the sum of the areas of the four large bases. Here's one common way to write this formula, where 'l' is length, 'w' is width and 'h' is height:
V = 2(l x w) + 2(l x h) + 2(w x h)
Volume
A regular, 3-dimensional object's volume is the product of the area of its base and its height. Returning to the rectangular prism example in the last section, you would multiply the area of one of the small bases by the height of the prism to get its volume. This formula can be written as V = l x w x h, since the area of the base is equal to length times width (l x w). For a cube, the formula is V = s^3, where 's' is the length of a side.
To find the volume of a cylinder, calculate the area of the circular base using the formula given in the first section, A = (pi)r^2. Then, multiply this by the height of the cylinder, 'h.' Putting this all together, the formula is V = (pi)r^2 * h.
The volume of a triangular prism is the product of the prism's height, 'h,' and the area of its base (V = Height * Area of the Base). You can find the area of the prism's triangular base using the formula A = 1/2 * b * h, where 'b' is the base of the triangle and 'h' is its height. Be careful not to confuse the height of the triangle with the height of the prism, or the area of the prism's base with the length of the triangle's base.
Other Articles You May Be Interested In
-
Does Your Child Need a Tutor?
Many children benefit from the instruction of a tutor, whether they're struggling with a learning disability or taking advanced courses through a gifted program. Taking the time to consider whether or not to hire a tutor means you're giving your child an opportunity to excel in the classroom.
-
How Can You Know if College Is Right for Your Child?
A prevailing school of thought is that most people need college in order to be successful. But this certainly may not always be the case. Quite simply, not everyone is college material. If your teen will soon be graduating from high school, you may need to contemplate whether college is right for your child.
We Found 7 Tutors You Might Be Interested In
Huntington Learning
- What Huntington Learning offers:
- Online and in-center tutoring
- One on one tutoring
- Every Huntington tutor is certified and trained extensively on the most effective teaching methods
K12
- What K12 offers:
- Online tutoring
- Has a strong and effective partnership with public and private schools
- AdvancED-accredited corporation meeting the highest standards of educational management
Kaplan Kids
- What Kaplan Kids offers:
- Online tutoring
- Customized learning plans
- Real-Time Progress Reports track your child's progress
Kumon
- What Kumon offers:
- In-center tutoring
- Individualized programs for your child
- Helps your child develop the skills and study habits needed to improve their academic performance
Sylvan Learning
- What Sylvan Learning offers:
- Online and in-center tutoring
- Sylvan tutors are certified teachers who provide personalized instruction
- Regular assessment and progress reports
Tutor Doctor
- What Tutor Doctor offers:
- In-Home tutoring
- One on one attention by the tutor
- Develops personlized programs by working with your child's existing homework
TutorVista
- What TutorVista offers:
- Online tutoring
- Student works one-on-one with a professional tutor
- Using the virtual whiteboard workspace to share problems, solutions and explanations