Plz solve the word problem
1) 225 m rope is painted in different colours. 1/3 portion is coloured in red, 2/5 of the remaining in green, 3/15 of the remaining in white and rest of the portion in black. What is the length of the black coloured portion.
2) The sum of two rational numbers is 9/25
and one of the rational numbers is 4/25
find the other
number.
3) Cost of one story book is 3/11
of the cost of an atlas. If cost of atlas is 451 rupees, find the
cost of story book.
plz solve it step by step
Answers
Radius (r1) of 1st circle = 19 cm
Radius (r2) or 2nd circle = 9 cm
Let the radius of 3rd circle be r.
Circumference of 1st circle = 2πr1 = 2π (19) = 38π
Circumference of 2nd circle = 2πr2 = 2π (9) = 18π
Circumference of 3rd circle = 2πr
Given that,
Circumference of 3rd circle = Circumference of 1st circle + Circumference of 2nd circle
2πr = 38π + 18π = 56π
Therefore, the radius of the circle which has circumference equal to the sum of the circumference of the given two circles is 28 cm.
Step-by-step explanation:
Areas related to circles- We already know the methods of finding perimeter and area of simple plane figures such as rectangles, squares, parallelograms, triangles, and circles. In this chapter, we will study about the areas related to circles. The first section is about the perimeter and area of a circle.
Area of the circle =
Given one of the number is −
7
4
Sum of the rational numbers is −1
5
2
⟹−
7
4
+x=−1
5
2
⟹x=
7
4
−(1+
5
2
)
⟹x=
7
4
−
5
7
⟹x=
35
20−49
⟹x=−
35
29
So the other number is −
35
29