Free Practical Geometry 02 Practice Test - 8th Grade

If measure of sides of a quadrilateral are given as AB = 4cm, CD = 5cm, and angles are given as ∠ ABC = 75, ∠ BCD = 35 and ∠ CDA = 135, can you construct a quadrilateral ABCD?

A.

Yes

B.

No

C.

With the measure of  DAB, Yes

D.

With the measure of BC, Yes

SOLUTION

Solution : D

We can't draw a unique quadrilateral with all the measurements which are given. This is because we need the measurement of two adjacent sides and 3 angles to construct the quadrilateral ABCD. But with BC, we will have 6 sets of measurements and two known adjacent sides. Hence, we will be able to construct the quadrilateral ABCD.

Can we draw a quadrilateral ABCD with following measurements: AB = 3cm, BC = 5cm, AD = 4cm, CD= 7cm and BD=8cm?

A.

No, it is impossible

B.

With the measure of extra angle, Yes

C.

With the measure of other diagonal, Yes

D.

Yes, definitely

SOLUTION

Solution : A

If we have the measures of all the sides of a quadrilateral and its one diagonal, we can draw two triangles and hence, form a quadrilateral.

ABCD comprises of two triangle  ADB &  CDB

In Δ ADB, AB = 3cm, BD = 8cm, and AD = 4cm

Since, AB + AD  < BD

So, quadrilateral ABCD can't be constructed.

Can you draw a unique triangle with any 3 possible measurements of sides or angles?

A.

Yes

B.

With 3 angles, Yes; With 3 sides, No

C.

With 3 sides, Yes; With 3 angles, No

D.

No, not possible

SOLUTION

Solution : C

Measurement of all the sides or 2 angles and 1 side or 1 angle and 2 sides are required to construct a unique triangle. Using 3 angles, we can construct many triangles, not a unique triangle. For e.g. there are infinite equilateral triangles though they have all the angles equal to 60.

A quadrilateral ABCD is to be constructed. What are the measurements required to construct the quadrilateral ABCD from the given options?

A.

AB, BC, CD and DA

B.

AB, BC, CD, DA and BD

C.

AB, BC, CD, AC and BD

D.

AB and BC

SOLUTION

Solution : B and C

We know that we need minimum 5 measurements from a quadrilateral to draw it.
In one option we have 5 measurements as AB, BC, CD, DA and BD. Here AB, BC, CD, DA are sides and BD is a diagonal.
The construction is possible.

AB, BC, CD, AC and BD. These are 3 sides and 2 diagonals. So, it is possible to construct the quadrilateral.

In other two options only 4 sides and 2 sides are mentioned. So construction is not possible.

We have a parallelogram ABCD with AC and BD as diagonals. In parallelogram ABCD,  ABC = 110,   DAC = 15,  CAB=25, AB = 5cm, CD = 7cm. Can we construct this parallelogram?

A.

Yes, of course

B.

C.

With AC, yes

D.

No, it is impossible

SOLUTION

Solution : D

Step1: Draw rough diagram of the parallelogram ABCD

Here,  DAC =  ACB= 15 - (1) (Alternate interior angles)
In  ABC,
A + B + C must be 180
A + B + C = 25 + 110 + 15             (from (1))
A + B + C = 150

The sum of angles in a triangle should always be equal to 180. So, this construction is not possible.

Is it possible to construct a unique quadrilateral ABCD with AB = 5cm, BC = 6cm, CD= 7cm ,  ABC = 45 and  BCD = 55?

A.

Yes, it is possible

B.

No, two such quadrilaterals can be constructed

C.

No, there can be infinite such quadrilaterals

D.

With the measure of one more side, yes

SOLUTION

Solution : A

Step 1: Draw AB = 5cm.

Step 2: At B, draw an angle of 45 and mark 6 cm along that angle. Mark the point as C.

Step 3: At C, draw an angle of 55 and mark 7cm along that angle. Mark the point as D.

Step 4: Join point A and D. So, quadrilateral ABCD can be constructed.

If we know that one side of a rectangle is 8 cm, can we construct a unique rectangle?

A.

Yes

B.

Yes, if the measurement of one angle is given.

C.

Yes, if the measurement of two angles are given.

D.

No, its not possible

SOLUTION

Solution : D

Rectangle is a special quadrilateral and minimum number of measures required to construct a rectangle is 2(length of 2 sides).
Since we only know one side of the rectangle. we can draw infinite rectangles. This is because the other side's length is not specified. For e.g.

If you are given AB = 5 cm, BC = 6 cm, CD = 7 cm, DA = 6 cm and   ABC= 60, can you draw a quadrilateral?

A.

Yes

B.

No

C.

Maybe

D. Atleast one more measurement is required

SOLUTION

Solution : A

Let us try to draw the quadrilateral:

Step 1: Draw BC = 6 cm.

Step 2: At B, draw an angle = 60. Along that angle, make an arc of 5 cm and mark it as point A.

Step 3: From A, draw an arc of 6 cm.

Step 4: From C, draw an arc of 7 cm such that it intersects the arc made from A. Mark the point of intersection as D.

Step 5: Join ABCD to complete the quadrilateral.

Is this quadrilateral unique? Yes it is.

If we move it, keeping all the angle length constant ABC will change. So, there is only one quadrilateral ABCD with AB = 5 cm, BC = 6 cm, CD = 7 cm, BA = 6 cm,  ABC= 60.

What is the minimum number of measurements required to construct a unique rhombus?

___

SOLUTION

Solution :

Since all the sides of a rhombus are equal, it means that if we know one side we know all the sides.

Now,  while constructing the rhombus we need to know at least one angle (as all the angles in a rhombus are not equal). Therefore, in total we need at least 2 measurements to construct a unique rhombus.

At least four measurements are required to draw a unique quadrilateral.

A.

True

B.

False

SOLUTION

Solution : B

Any four measurements are not sufficient to draw a unique quadrilateral.
Let us take AB = 5cm, BC = 4cm, AD = 5cm, CD = 3cm.

We shall start constructing with any one side (say AB). Construct AB with length 5cm. Now, as we have BC and AD. We can draw arcs with BC and AD as radii. But we cannot mark the points C and D based on the data given. So, we need more data to draw a quadrilateral.