141
State true or false.
a) Inmedian, data should always be arranged in descending order.
.) Exterior angle is equal to sum of two interior opposite angles.
c) In & AX and APQR. if all the three corresponding pairs of sides are equal the
triangles are congruent by SSS rule.
4 The number which appears minimum times in the given data is called "Mode
Answers
Step-by-step explanation:
Question 1.
The sides of a triangle have lengths (in cm) 10,6.5 and a, where a is a whole number. The minimum value that a can take is
(a) 6
(b) 5
(c) 3
(d) 4
Solution:
(d) Lengths of sides of the triangle are 10 cm, 6.5 cm and a cm.
Since, sum of lengths of any two sides of a triangle is greater than length of third side.
∴ 10 + 6.5 > a, 10+ > 6.5, 6.5 + a > 10
⇒ 16.5 > a, a > -3.5, a > 3.5
Given that a is a whole number
∴ Minimum value that a can take is 4.
Question 2.
Triangle DEF of the given figure is a right triangle with ∠E = 90°.
What type of angles are ∠D and ∠F?
(a) They are equal angles
(b) They form a pair of adjacent angles
(c) They are complementary angles
(d) They are supplementary angles
NCERT Exemplar Class 7 Maths Chapter 6 Triangles 1
Solution:
(c) ∠D + ∠E + ∠F = 180° [Angle sum property of a triangle]
∠D + ∠F = 180°- 90° [∵∠E = 90° (given)]
= 90°
∴ ∠D and ∠F are complementary angles.