Advertisements
Advertisements
प्रश्न
The area of a rectangle of length 21 cm and diagonal 29 cm is __________
विकल्प
609 cm2
580 cm2
420 cm2
210 cm2
Advertisements
उत्तर
420 cm2
Explanation;
Hint:
length = 21 cm
diagonal = 29 cm
By the converse of Pythagoras theorem,
AB2 + BC2 = AC2
212 + x2 = 292
x2 = 841 – 441
400 = 202
x = 20 cm
Now area of the rectangle = length × breadth.
i.e AB × BC
= 21 cm × 20 cm
= 420 cm2
APPEARS IN
संबंधित प्रश्न
In ∆PQR, PQ = √8 , QR = √5 , PR = √3. Is ∆PQR a right-angled triangle? If yes, which angle is of 90°?
In a ∆ABC, AD is the bisector of ∠BAC. If AB = 8 cm, BD = 6 cm and DC = 3 cm. The length of the side AC is
Two poles of heights 6 m and 11 m stand vertically on a plane ground. If the distance between their feet is 12 m, what is the distance between their tops?
The incentre is equidistant from all the vertices of a triangle
Check whether given sides are the sides of right-angled triangles, using Pythagoras theorem
30, 40, 50
Check whether given sides are the sides of right-angled triangles, using Pythagoras theorem
24, 45, 51
A rectangle having length of a side is 12 and length of diagonal is 20, then what is length of other side?
In ∆ABC, AB = `6sqrt(3)` cm, AC = 12 cm, and BC = 6 cm then m∠A = ?
If a triangle having sides 8 cm, 15 cm and 17 cm, then state whether given triangle is right angled triangle or not
In a right angled triangle, right-angled at B, lengths of sides AB and AC are 5 cm and 13 cm, respectively. What will be the length of side BC?
