Sujeet Kumar

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

Question 1.In each pair of triangles given below, parts shown by identical marks are congruent. State the test and the one-to-one correspondence of vertices by which triangles in each pair are congruent. Also state the remaining congruent parts. Solution:i. In ∆MST and ∆TBM,∴ side MS ≅ side TB … [Given]m∠MST = m∠TBM = 90° … … Read more

Question 1.In each pair of triangles in the following figures, parts bearing identical marks are congruent. State the test and correspondence of vertices by which triangles in each pair are congruent.i. ii.iii.iv.v.Solution:i.The two triangles are congruent by SAS test in the correspondence XWZ ↔ YWZ. ii.The two triangles are congruent by hypotenuse-side test in the … Read more