Sujeet Kumar

Question 1.In each example given below, radius of base of a cylinder and its height are given. Then find the curved surface area and total surface area.i. r = 7 cm, h = 10 cmii. r = 1.4 cm, h = 2.1 cmiii. r = 2.5 cm, h = 7 cmiv. r = 70 cm, … Read more

Question 1.Find the volume of a box if its length, breadth and height are 20 cm, 10.5 cm and 8 cm respectively.Given: For cuboid shaped box,length (l) = 20 cm, breadth (b) = 10.5 cm and height (h) = 8cmTo find: Volume of a boxSolution:Volume of a box = l x b x h= 20 … Read more

iii. Radius of the circle (r) = 17.5 cm … [Given]Area of the circle = πr²= x(17.5)²= x 17.5 x 17.5= 22 x 2.5 x 17.5= 962.5 sq. cm Question 2.Areas of some circles are given below, find their diameters.i. 176 sq.cmii. 394.24 sq. cmiii. 12474 sq. cmSolution:i. Area of the circle =176 sq. cm … Read more

Question 1.Find the areas of given plots. (All measures are in meters.) ∴ Area of plot ABCDE= A(∆ABE) + A(∆BCE) + A(∆EDC)= 216 + 336 + 224= 776 sq. m∴ The area of the given plot is 776 sq.m.[Note: In the given figure, we have taken l(DF) = 16 m]

∴ The area of the triangle is 756 sq.cm. Question 2.Look at the measures shown in the given figure and find the area of ☐PQRS.= 270 sq.mIn ∆PSR, m∠PSR = 90°[l(PR)]² = [l(PS)]² + [l(SR)]²…[Pythagoras theorem]= (36)² + (15)²= 1296 + 225∴ l(PR)² = 1521∴ l(PR) = 39m…[Taking square root of both sides]In ∆PQR, a … Read more

Question 1.In the given figure, ☐ABCD is a trapezium, side AB || side DC, l(AB) = 13 cm, l(DC) = 9 cm, l(AD) = 8 cm, find the area ☐ABCD. Question 3.☐PQRS is an isosceles trapezium. l(PQ) = 7 cm, seg PM ⊥ seg SR, l(SM) = 3 cm. Distance between two parallel sides is … Read more

Question 3.If perimeter of a rhombus is 100 cm and length of one diagonal is 48 cm, what is the area of the quadrilateral?Solution:Let ₹ABCD be the rhombus. Diagonals AC and BD intersect at point E.In ∆ADE,m ∠AED = 90° …[Diagonals of a rhombus are perpendicular to each other]∴ [l(AD)]² = [l(AE)]² + [l(DE)]² … … Read more

Question 1.If base of a parallelogram is 18 cm and its height is 11 cm, find its area.Solution:Given, base = 18 cm, height = 11 cmArea of a parallelogram = base × height= 18 × 11= 198 sq.cm∴ Area of the parallelogram is 198 sq.cm. Question 2.If area of a parallelogram is 29.6 sq. cm … Read more

Question 1. On the construction work of a flyover bridge there were 320 workers initially. The number of workers were increased by 25% every year. Find the number of workers after 2 years.Solution:Here, P = Initial number of workers = 320R = Increase in the number of workers per year = 25%N = 2 yearsA … Read more

Chapter 14 Compound Interest Set 14.1 Question 1.Find the amount and the compound interest. No Principal (Rs) Rate (p.c.p.a.) Duration (years) i. 2000 5 2 ii. 5000 8 3 iii. 4000 7.5 2 Solution:i. Here P = Rs 2000, R = 5 p.c.p.a. and N = 2 years= 5 × 441∴ A = Rs 2205I … Read more