## Plans and elevations (Bird’s eye view) of 3D shapes

Non-verbal Reasoning Type 13: Plans and Elevations of 3D shapes

When an architect designs a building  he/she has to make 2-dimensional drawings to show what the building will look like from each side. These drawings are called plans and elevations.

Plan and elevations are all different perspectives of the same 3D shape.

The Plan

The view from the top is called the plan.

The plan is just a bird’s eye view of the shape.

Front and Side elevations

The views from the front and sides are called the elevations.

In a question, you will get an indication of which perspective is the front and which one is the side.

You will also be given a grid on which you can do your drawings of the plan and the elevations.

In this type of questions you are given a 3D shape and you must identify the drawings of the plan, the front elevation and the side elevation.

In this video we use animations to show the pupil what the plan and elevations of a 3D shape will look like.

Plans and Elevations of 3D shapes (Bird’s eye view) VIDEO!

## For the Eleven Plus and CEM exams, pupils need to be able to

• Substitute numbers into formulae and evaluate the formula.
• Example 1: Work out the value of 3a – 2b + 4c if a = 5, b = 3 and c = 2
• Example 2: C = 5 x (F – 32) ÷ 9. What is C when F is (a) 50 and (b) 5?
• Simplify algebraic expressions (collect like terms).
• The angles of a triangle are a, 2a and 2a + 30. Work out the value of a.
• Solve equations with the unknown on one side.
• What is n if 6n – 5 = 37?
• Solve equations with the unknown on both sides (accompanying video)
• Work out the value of x if 5x + 7 = 25 – x
• Solve equations with 2 or more variables.
• There are 13 animals in the barn. Some are chickens and some are pigs. There are 40 legs in all. How many of each animal are there?
• Form algebraic expressions and equations (accompanying video)
• The newsagent charges x pence for a biro and y pence for a pencil. Write down an expression using x and y for the cost of three biros and two pencils.

Forming expressions and equations Video!

Solve equations with the unknown on both sides of the equal sign Video!

## Area and Perimeter of compound shapes.

11 Plus Entrance Exams including CEM (Durham University) exams.

Area and Perimeter of compound shapes.

This is an important and a popular topic for all the entrance exams (11 plus as well as independent school entrance exams). In the CSSE exam there was a question on composite shapes every year for the past 11 years. It also appeared in the CEM (Durham University) exams over the past two years.

For the 11 plus entrance exam, pupils need to be able to

• work out the perimeter of 2-dimensional shapes:
• normally some of the side-lengths are unknown and pupils must first work out the lengths of all the sides.
• all sides can be given as letters and pupils need to use algebraic manipulation to find the perimeter.
• work out the area of the following 2-dimensional shapes
• area of a square
• area of a rectangle
• area of a parallelogram
• area of a triangle
• area of a trapezium
• work out the area of compound/composite shapes,
• work out the number of tiles needed to cover a certain area,
• work out the amount of paint needed to paint a certain area,
• find the lengths of sides from given coordinates to work out the area and perimeter.

The accompanying videos show you how to work out the area of a compound shape and how to work out the number of tiles needed to cover a certain area.

Area of compound shapes Video

Number of tiles needed to cover a certain area video