Page 185 - ICSE Math 7

(d) The three altitudes of a triangle are _________________ and their point of intersection is
known as _______________.
(e) In a right-angled triangle, the square of the ________________ is equal to the sum of the
squares of the other two sides.

PRACTICE TIME

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.

4. In the adjacent figure, find A D
∠ABD + ∠DBC + ∠BCD + ∠CDB + ∠BDA + ∠DAB. C

B
5. The base angle of an isosceles triangle is double of its vertical angle. Find all its angles.
6. In the given figures, find the values of x and y:

y
x 85°
(a) (b) y

140° 115° x 130°

7. A ladder reaches a window which is 12 m above the ground on one side of the street. Keeping
its foot at the same point, the ladder is turned to the other side of the street to reach a window
5 m high. Find the width of the street if the length of the ladder is 13 m.
8. One angle of the triangle is 54° and the other two angles are in the ratio 2 : 5. Find the angles.

9. Ria walks 80 m towards north from her place to reach Jia’s place. From there they walk 60 m
towards east to reach a library. How far is the library from Ria’s place?

10. Ananya has to make the cover page of a book. The size of the cover page should not be more
than 10 inches diagonally. If she decides to keep the width 6 inches, what should be the maximum
length of the cover page?

THINK SMART

1. An angle of a triangle is equal to the sum of the other two angles. Also, one of the angles is
one-third of the largest angle, find the angles of the triangle.

35° x 85°
2. Find the value of the unknown angles x and y marked in the given y
figure.

3. Find all the angles of a triangle, given that the angles are in the ratio 8 : 4 : 3.

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