Area - triangles, quadrilaterals, compound shapes

There are 53 NRICH Mathematical resources connected to Area - triangles, quadrilaterals, compound shapes
Rati-o
problem

Rati-o

Age
11 to 14
Challenge level
filled star filled star filled star
Points P, Q, R and S each divide the sides AB, BC, CD and DA respectively in the ratio of 2 : 1. Join the points. What is the area of the parallelogram PQRS in relation to the original rectangle?
Maths filler 2
problem

Maths filler 2

Age
14 to 16
Challenge level
filled star filled star empty star
Can you draw the height-time chart as this complicated vessel fills with water?
Equilateral Areas
problem

Equilateral areas

Age
14 to 16
Challenge level
filled star filled star empty star
ABC and DEF are equilateral triangles of side 3 and 4 respectively. Construct an equilateral triangle whose area is the sum of the area of ABC and DEF.
Bicentric Quadrilaterals
problem

Bicentric quadrilaterals

Age
14 to 16
Challenge level
filled star filled star filled star
Investigate the properties of quadrilaterals which can be drawn with a circle just touching each side and another circle just touching each vertex.
Triangle Island
problem

Triangle island

Age
7 to 11
Challenge level
filled star filled star filled star
You have pitched your tent (the red triangle) on an island. Can you move it to the position shown by the purple triangle making sure you obey the rules?
Dividing the Field
problem

Dividing the field

Age
14 to 16
Challenge level
filled star empty star empty star
A farmer has a field which is the shape of a trapezium as illustrated below. To increase his profits he wishes to grow two different crops. To do this he would like to divide the field into two trapeziums each of equal area. How could he do this?
Halving the Triangle
problem

Halving the triangle

Age
16 to 18
Challenge level
filled star empty star empty star
Draw any triangle PQR. Find points A, B and C, one on each side of the triangle, such that the area of triangle ABC is a given fraction of the area of triangle PQR.
Kissing Triangles
problem

Kissing triangles

Age
11 to 14
Challenge level
filled star filled star empty star
Determine the total shaded area of the 'kissing triangles'.
Squ-areas
problem

Squ-areas

Age
14 to 16
Challenge level
filled star filled star filled star
Three squares are drawn on the sides of a triangle ABC. Their areas are respectively 18 000, 20 000 and 26 000 square centimetres. If the outer vertices of the squares are joined, three more triangular areas are enclosed. What is the area of this convex hexagon?
From all corners
problem

From all corners

Age
14 to 16
Challenge level
filled star filled star filled star
Straight lines are drawn from each corner of a square to the mid points of the opposite sides. Express the area of the octagon that is formed at the centre as a fraction of the area of the square.