In figures, (i) and (ii) DE || BC. Find EC in (i) and AD in (ii).

Solution : (i)  In figure (i) Since DE || BC, therefore \(AD\over DB\) = \(AE\over EC\) \(\implies\)  \(1.5\over 3\) = \(1\over EC\) \(\implies\)  EC = 2 cm. (ii)  In figure (ii), Since DE || BC, therefore \(AD\over DB\) = \(AE\over EC\) \(\implies\)  \(AD\over 7.2\) = \(1.8\over 5.4\) \(\implies\)  AD = 2.4 cm.

Give two different examples of pair of (i) similar figures (ii) non-similar figures.

Solution : (i)  Pair of similar figures examples are : (a)  any two circles. (b)  any two squares. (ii)  Pair of non-similar figures examples are : (a)  scalene triangle and equilateral triangle. (b)  equilateral triangle and right angled triangle.

Fill in the blanks using the correct word given in the brackets :

Question : Fill in the blanks using the correct word given in the brackets : (i)  All circles are ………….. . (congruent, similar) (ii)  All squares are ……….. . (similar, congruent). (iii)  All  …………….    triangles are similar. (isosceles, equilateral) Solution  : (i)  Similar (ii) similar (iii) equilateral

ABCD is a cyclic quadrilateral as shown in figure. Find the angles of the cyclic quadrilateral.

Solution : We know that the sum of opposite angles of cyclic quadrilateral is 180 degrees. Angles A and C, Angles B and D form pairs of opposite angles in the given cyclic quadrilateral ABCD. \(\angle\)A + \(\angle\)C = 180   and  \(\angle\)B + \(\angle\)D = 180 \(\implies\)  (4y + 20) + 4x = 180   and  …

ABCD is a cyclic quadrilateral as shown in figure. Find the angles of the cyclic quadrilateral. Read More »

Draw the graphs of the equation 5x – y = 5 and 3x – y = 3. Determine the coordinates of the vertices of the triangle formed by these lines and the y-axis.

Solution :  The given linear equations are 5x – y = 5           ………(1) 3x – y = 3            ………(2) From equation (1),   y = 5x – 5 When x = 1, y = 5 – 5 = 0 When x = 2, y = 10 – …

Draw the graphs of the equation 5x – y = 5 and 3x – y = 3. Determine the coordinates of the vertices of the triangle formed by these lines and the y-axis. Read More »

In \(\triangle\) ABC, \(\angle\)C = 3\(\angle\)B = 2(\(\angle\)A + \(\angle\)B). Find the three angles of the triangle.

Solution : Given,  \(\angle\)C = 2(\(\angle\)A + \(\angle\)B)           …….(1) Adding 2\(\angle\)C on both sides in equation (1), we get \(\angle\)C + 2\(\angle\)C = 2(\(\angle\)A + \(\angle\)B)  + 2\(\angle\)C \(\implies\)  3\(\angle\)C = 2(\(\angle\)A + \(\angle\)B + \(\angle\)C) Since, \(\angle\)A + \(\angle\)B + \(\angle\)C = 180 degrees \(\implies\)  \(\angle\)C = \(2\over 3\) \(\times\) …

In \(\triangle\) ABC, \(\angle\)C = 3\(\angle\)B = 2(\(\angle\)A + \(\angle\)B). Find the three angles of the triangle. Read More »

The students of a class are made to stand in rows. If 3 students are extra in a row, there would be 1 row less. If 3 students are less in a row, there would be 2 rows more. Find the number of students in the class.

Solution : Let students in each row be x. And Let number of rows be y. then, total number of students = xy Case 1 : When 3 students are extra in a row, then number of rows becomes (y – 1) xy = (x + 3)(y – 1) \(\implies\)  x – 3y + 3 …

The students of a class are made to stand in rows. If 3 students are extra in a row, there would be 1 row less. If 3 students are less in a row, there would be 2 rows more. Find the number of students in the class. Read More »

A train covered a certain distance at a uniform speed. If the train would have been 10 km/hr faster, it would have taken 2 hours less than the scheduled time. And if the train were slower by 10 km/hr, it would have taken 3 hours more than the scheduled time. Find the distance covered by the train.

Solution : Let x km/hr  be the original speed of the train and y hrs be the time taken by the train to complete the journey. Then, Distance covered = xy km Case 1 : When  speed = (x + 10) km/hr time taken = (y – 2) hr Distance = (x + 10) (y …

A train covered a certain distance at a uniform speed. If the train would have been 10 km/hr faster, it would have taken 2 hours less than the scheduled time. And if the train were slower by 10 km/hr, it would have taken 3 hours more than the scheduled time. Find the distance covered by the train. Read More »

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