Can someone please help me with something?
Find the surface area of the prism. 5 m, 12m, 9m. its rectangular
Also, Find the surface area of the cylinder to the nearest tenth of a square unit, 4cm, 12.4 cm.
I dont quite understand this unit, im bad a geometry, sorry.
SA = 2(5 * 12) + 2(12 * 9) + 2(5 * 9)
https://www.mathsisfun.com/geometry/cylinder.html
Thank you Ms. Sue. You're the best ;p
Of course, I'd be happy to help you with both of these questions!
To find the surface area of a rectangular prism, you need to find the areas of each of its six faces and then sum them up. The formula for the surface area of a rectangular prism is:
Surface Area = 2lw + 2lh + 2wh
where l, w, and h are the length, width, and height of the prism, respectively. In this case, you have given the dimensions as 5m, 12m, and 9m, so you can substitute these values into the formula:
Surface Area = 2(5m)(12m) + 2(5m)(9m) + 2(12m)(9m)
Now you can simplify and compute the answer. Multiply each pair of numbers and then add them up:
Surface Area = 120m² + 90m² + 216m²
Surface Area = 426m²
Therefore, the surface area of the rectangular prism is 426 square meters.
Moving on to the second question, to find the surface area of a cylinder, you need to find the sum of the areas of the two circular bases and the lateral surface area. The formula for the surface area of a cylinder is:
Surface Area = 2πr² + 2πrh
where r is the radius of the cylinder's base, and h is the height. In this case, you have given the dimensions as 4cm and 12.4cm, so you can substitute these values into the formula:
Surface Area = 2π(4cm)² + 2π(4cm)(12.4cm)
Now you can simplify and compute the answer. First, square the radius and then perform the multiplications:
Surface Area = 2π(16cm²) + 2π(4cm)(12.4cm)
Surface Area = 32πcm² + 99.2πcm²
Surface Area ≈ 131.2πcm²
The value of π is approximately 3.14159, so you can use this approximation to calculate a decimal approximation of the surface area:
Surface Area ≈ 131.2 × 3.14159 cm²
Surface Area ≈ 411.63 cm² (rounded to the nearest tenth)
Therefore, the surface area of the cylinder, to the nearest tenth of a square unit, is approximately 411.63 square centimeters.
You're welcome.
And thank you.