RD Sharma Solutions Class 9 Maths Chapter 12: In Chapter 12 of RD Sharma's Class 9 Maths book, students learn about Heron’s Formula, which helps find the area of a triangle using its sides. These solutions help students understand difficult concepts in an easy way. With RD Sharma Solutions, students can learn how to find the area of a triangle using its side lengths. These solutions explain things in a simple manner, making it easier for students to understand. By using these solutions, students can get better at math and do well in their studies.
For students looking for help, RD Sharma's Solutions are a great option. They explain each step clearly and are designed to match students' abilities. You can get the solutions for Chapter 12 of Class 9 Maths for free in PDF format by clicking the links below. These solutions are based on the latest CBSE syllabus for the 2024-25 exams.CBSE Class 9 Science Syllabus 2024-25
RD Sharma Solutions Class 9 Maths Chapter 12 PDF
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Question 1: Find the area of the quadrilateral ABCD in which AB = 3 cm, BC = 4 cm, CD = 4 cm, DA = 5 cm and AC = 5 cm.
Solution:
Question 2: The sides of a quadrilateral field, taken in order, are 26 m, 27 m, 7 m, and 24 m, respectively. The angle contained by the last two sides is a right angle. Find its area.
Solution:
Question 3: The sides of a quadrilateral, taken in order as 5, 12, 14, and 15 meters, respectively, and the angle contained by the first two sides is a right angle. Find its area.
Solution:
Question 4: A park in the shape of a quadrilateral ABCD has ∠ C = 90 0 , AB = 9 m, BC = 12 m, CD = 5 m, AD = 8 m. How much area does it occupy?
Solution:
In the right △BCD,
From Pythagoras theorem; BD 2 = BC 2 + CD 2 BD 2 = 12 2 + 5 2 = 144 + 25 = 169 BD = 13 m Area of △BCD = 1/2×BC×CD = 1/2×12×5 = 30 Area of △BCD = 30 m 2Now, In △ABD,
All sides are known, Apply Heron’s Formula:Question 5: Two parallel sides of a trapezium are 60 m and 77 m and the other sides are 25 m and 26 m. Find the area of the trapezium.
Solution:
In the right △ADE ,
From Pythagoras theorem, DE 2 = AD 2 − AE 2 DE 2 = 25 2 − x 2 ….(2)In right △BCF
From Pythagoras theorem, CF 2 = BC 2 − BF 2 CF 2 = 26 2 − (17−x) 2 [Uisng (1)] Here, DE = CF So, DE 2 = CF 2 (2) ⇒ 25 2 − x 2 = 26 2 − (17−x) 2 625 − x 2 = 676 – (289 −34x + x 2 ) 625 − x 2 = 676 – 289 +34x – x 2 238 = 34x x =7 (2) ⇒ DE 2 = 25 2 – (7) 2 DE 2 = 625−49 DE = 24 Area of trapezium = 1/2×(60+77)×24 = 1644 Area of trapezium is 1644 m 2 (Answer)Question 6: Find the area of a rhombus whose perimeter is 80 m and one of whose diagonal is 24 m.
Solution:
Question 7: A rhombus sheet, whose perimeter is 32 m and whose diagonal is 10 m long, is painted on both the sides at the rate of Rs 5 per m 2 . Find the cost of painting.
Solution:
The perimeter of a rhombus = 32 m We know, Perimeter of a rhombus = 4×side ⇒ 4×side = 32 side = a = 8 m Each side of the rhombus is 8 m AC = 10 m (Given)Question 1: Find the area of a triangle whose base and altitude are 5 cm and 4 cm, respectively.
Solution :
Given: Base of a triangle = 5 cm and altitude = 4 cm Area of triangle = 1/2 x base x altitude = 1/2 x 5 x 4 = 10 The area of the triangle is 10 cm 2 .Question 2: Find the area of a triangle whose sides are 3 cm, 4 cm and 5 cm, respectively.
Solution:
Given: Sides of a triangle are 3 cm, 4 cm and 5 cm, respectively Apply Heron’s Formula:Question 3: Find the area of an isosceles triangle having the base x cm and one side y cm.
Solution:
Question 4: Find the area of an equilateral triangle having each side 4 cm.
Solution: Each side of an equilateral triangle = a = 4 cm
Formula for Area of an equilateral triangle = ( √3/4 ) × a² = ( √3/4 ) × 4² = 4√3 The area of an equilateral triangle is 4√3 cm 2 .Question 5: Find the area of an equilateral triangle having each side x cm.
Solution:
Each side of an equilateral triangle = a = x cm Formula for Area of an equilateral triangle = ( √3/4 ) × a² = ( √3/4 ) × x² = x 2 √3/4 The area of an equilateral triangle is √3x 2 /4 cm 2 .CBSE Class 9 Maths Syllabus | CBSE Class 9 Science Syllabus |
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