Envision Math Grade 8 Volume 1 Chapter 8 Solve Problems Involving Surface Area And Volume
Page 412 Exercise 1 Answer
A three dimensional object is in three dimensions having length, width and height.
Example: Cubes, prisms, pyramids, spheres, cones, and cylinders are all examples of three-dimensional objects.
Volume is the product of length, width and height.
Surface areas is the sum of products of length, width and height taken two at a time.
Volume of a prism = cross-sectional area × length.
The surface area of a 3D shape is the total area of all its faces.
Page 415 Exercise 1 Answer
The figure of circle is shown as
Here r is know as radius from center to circle which is constant throughout.
The radius is the distance from the center to the edge of a circle.
Page 415 Exercise 2 Answer
The objects around you are three-dimensional.
A three dimensional object is in three dimensions having length, width and height.
Example: Cubes, prisms, pyramids, spheres, cones, and cylinders are all examples of three-dimensional objects.
Day to day life examples: cup, mobile phone, ball and bottle.
A shape that has length, width, and height is three dimensional.
Page 415 Exercise 3 Answer
A three dimensional object is in three dimensions having length, width and height.
Example: Cubes, prisms, pyramids, spheres, cones, and cylinders are all examples of three-dimensional objects.
Any side of a cube can be considered a base.
Any side of a cube can be considered a base.
Page 415 Exercise 5 Answer
Given:
The ________________ of a circle is a line segment that passes through its center and has endpoints on the circle.
The distance from one point on a circle through the center to another point on the circle.
It is also the longest distance across the circle.
The diameter of a circle is a line segment that passes through its center and has endpoints on the circle.
Hence, the diameter of a circle is a line segment that passes through its centre and has endpoints on the circle.
Page 415 Exercise 7 Answer
Given:
9⋅3.14
To find the product:
Multiply 9 with 3.14.
We have,
9⋅3.14
Multiply the numbers:
= 28.26
It follows that the product is 28.26.
Hence, the product is 28.26.
Page 415 Exercise 8 Answer
Given:
4.2⋅10.5
To find the product:
Multiply 4.2 with 10.5.
We have,
4.2⋅10.5
Multiply the numbers:
= 44.10
It follows that the product is 44.10.
Hence, the product is 44.10.
Page 415 Exercise 9 Answer
Given:
Hence, the area of the given circle is 100.48cm2.
Page 415 Exercise 10 Answer
Given:
To find the area of the circle:
First, find r using the diameter and then plug the value of r,π in the area of the circle formula.
So, the area of the circle is 56.52 cm2
Hence, the area of the given circle is 56.52cm2.
Page 415 Exercise 11 Answer
Given:
To find the missing value of x:
Use the Pythagorean Theorem and apply it to the given right triangle.
Hence, the missing value is x = 5in.
Page 415 Exercise 12 Answer
Given:
To find the missing value of x:
Use the Pythagorean Theorem and apply it to the given right triangle.
Hence, the missing value is x = 18m.