Page 180 - Start Up Mathematics_7

6. The median of a triangle always lies inside the triangle.

7. The point of intersection of altitudes may lie outside the triangle.

Fill in the Blanks
1. In a triangle, the line joining the vertex to the midpoint of the opposite side is known as
____________.

2. The perpendicular drawn from the vertex of a triangle to the opposite side is known as
___________.
3. The three medians of a triangle meet at a ______________ known as the _______________.
4. The three altitudes of a triangle are _________________ and their point of intersection is
known as _______________.
5. In a right-angled triangle, the square of the ________________ is equal to the sum of the
squares of the other two sides.

6. The third side of a triangle whose two sides measure 1 cm and 100 cm is greater than _________
and less than _____________.

Answer in One Word or a Line
1. Can a right-triangle be equilateral?

2. Can you have a triangle with three acute angles?
3. Can you have a triangle with all the three angles greater than 60º?

4. Can you have a right triangle with an obtuse angle?
5. The exterior angles of a ∆ ABC, having vertex C is equal to sum of which two angles?
6. State Pythagoras theorem.
7. Can an isosceles triangle be right-angled?

let’s evaluate

1. If one angle of a triangle is 90° and the other two angles are in the ratio 1 : 2, find the angles.
2. A man goes 35 m due west and then 12 m due north. How far is he from the starting point?

2
3. The two sides of a right-angled triangle are equal and the square of its hypotenuse is 50 cm .
Find the length of each side. A D
4. In the adjacent figure, find

∠ABD + ∠DBC + ∠BCD + ∠CDB + ∠BDA + ∠DAB.
C
5. In the given figures, find the values of x and y:

B

y
x 85°
(a) (b)
y

140° 115° x 130°

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