NCERT Class 7 Mathematics

CONGRUENCE OF TRIANGLES 139 Fig 7.11 Appu : Alright. Let me give the lengths of all the three sides. In ΔABC, I have AB = 5cm, B ...

140 MATHEMATICS EXAMPLE 3 In Fig 7.13, AD = CD and AB = CB. (i) State the three pairs of equal parts in ΔABD and ΔCBD. (ii) Is Δ ...

CONGRUENCE OF TRIANGLES 141 Fig 7.15 A BCD In Fig 7.15, AB = AC and D is the mid-point of BC. (i) State the three pairs of equa ...

142 MATHEMATICS Appu : So, what shall we do? Tippu : More information is needed. Appu : Then, let me modify my earlier statement ...

CONGRUENCE OF TRIANGLES 143 D EF35° 6cm 4cm SOLUTION (a) Here, AB = EF ( = 7 cm), BC = DE ( = 5 cm) and included∠B = included ∠E ...

144 MATHEMATICS In Fig 7.24, measures of some parts of the triangles are indicated. By applying SAS congruence rule, state the ...

CONGRUENCE OF TRIANGLES 145 SOLUTION For ASA congruence rule, we need the two angles between which the two sides BC and RP are i ...

146 MATHEMATICS Given below are measurements of some parts of two triangles. Examine whether the two triangles are congruent or ...

CONGRUENCE OF TRIANGLES 147 EXAMPLE 8 Given below are measurements of some parts of two triangles. Examine whether the two trian ...

148 MATHEMATICS In Fig 7.32, measures of some parts of triangles are given.By applying RHS congruence rule, state which pairs o ...

CONGRUENCE OF TRIANGLES 149 We now turn to examples and problems based on the criteria seen so far. EXERCISE 7.2 Which congruen ...

150 MATHEMATICS You have to show that ΔAMP ≅ΔAMQ. In the following proof, supply the missing reasons. Steps Reasons (i) PM = QM ...

CONGRUENCE OF TRIANGLES 151 Explain, why ΔABC≅ΔFED. Enrichment activity We saw that superposition is a useful method to test c ...

152 MATHEMATICS ASA Congruence of two triangles: Under a given correspondence, two triangles are congruent if two angles and th ...

8 .1 INTRODUCTION In our daily life, there are many occasions when we compare two quantities. Suppose we are comparing heights o ...

154 MATHEMATICS In the given cases, we write the ratio of the heights as : Heena’s height : Amir’s height is 150 : 75 or 2 : 1. ...

COMPARING QUANTITIES 155 SOLUTION Last year, Wins: Losses = 8 : 2 = 4 : 1 This year, Wins: Losses = 4 : 2 = 2 : 1 Obviously, 4 : ...

156 MATHEMATICS SOLUTION Arun does it like this Meera does it like this Let distance = x km 2 cm means 1000 km. then, 1000 : x = ...

COMPARING QUANTITIES 157 THINK, DISCUSS AND WRITE An ant can carry 50 times its weight. If a person can do the same, how much wo ...

158 MATHEMATICS To understand this, let us consider the following example. Rina made a table top of 100 different coloured tiles ...