Tiêu đề WK10 - Y3 - MATH - HW - GEOMETRY - AN.docx.pdf ✅

Question 1: Step 1: The sum of the areas of all the faces of a cube equals 384 square centimetres. 6a^2 = 384 a^2 = 384/6 a^2 = 64 a = 8 So, the side length of the cube is 8 cm. Step 2: The volume of the cube is - 8 * 8 * 8 = 512 cubic cm. Answer: E. 512 cubic cm Question 2: Step 1: The longer side of the rectangle is 15 metres. The longer side of the garden is 6 metres longer than the shorter side. Shorter side is 15 - 6 = 9 metres. Step 2: The perimeter is - 2(15 + 9) = 48 metres Answer: E. 48 metres Question 3: Step 1: The average (arithmetic mean) of the length of the sides of a right triangle is 10 centimetres. Step 2: Then, the perimeter of the triangle is - 3 * 10 = 30 cm. Answer: C. 30 cm Question 4: ©Scholarly 2025. All rights reserved. All digital content and materials provided are proprietary and protected under copyright law. Any reproduction or sharing of digital files, including screenshots, recordings, or downloads, is strictly prohibited without the prior written consent of Scholarly. 1
Step 1: A rectangle is formed by joining three identical squares, each with a side length of 3 centimetres, side-by-side. Step 2: The perimeter of the rectangle is - 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3 = 24 cm. Answer: C. 24 cm Question 5: Step 1: While doing house renovations, Angela increased the length of her rectangular-shaped window by 40 percent and decreased its width by 20 percent. Say the original length is 100 units and width is 50 units. Then, the area is - Area = 100 * 50 = 5000 square units. Step 2: The new length is 100 + 40% = 140 units. The width is 50 - 20% = 40 units. The area is - 140 * 40 = 5600 square units. The increased are is - 5600 - 5000 = 600 square units. 600/5000 * 100 = 12%. Answer: B. Increased by 12 percent Question 6: Step 1: The area of two given rectangles is the same. Area of red rectangle is - 5 * 24 = 120 square cm. Step 2: Say the length of the other side of the yellow rectangle is x cm. 6x = 120 x = 120/6 = 20 cm. ©Scholarly 2025. All rights reserved. All digital content and materials provided are proprietary and protected under copyright law. Any reproduction or sharing of digital files, including screenshots, recordings, or downloads, is strictly prohibited without the prior written consent of Scholarly. 2
Answer: D. 20 cm Question 7: Step 1: The above two triangles have the same perimeter. The perimeter of the yellow triangle is - 5 + 4 + 6 = 15 cm. Step 2: The side length of green triangle is - 15/3 = 5 cm. Answer: B. 5 cm Question 8: Step 1: The rectangular painting is 8 metres long and 5 metres wide. The area of rectangular painting is - 8 * 5 = 40 square metres. Step 2: Then, the area of square painting is - 40/2 = 20 square metres. Answer: A. 20 square metres Question 9: Step 1: The second side of the triangle is 10 centimetres. The first side of a triangle is 2 centimetres shorter than the second side, and the third side is 2 centimetres longer than the second side. Step 2: First side = 10 - 2 = 8 cm. Third side = 10 + 2 = 12 cm The perimeter of the triangle is - 10 + 8 + 12 = 30 cm. ©Scholarly 2025. All rights reserved. All digital content and materials provided are proprietary and protected under copyright law. Any reproduction or sharing of digital files, including screenshots, recordings, or downloads, is strictly prohibited without the prior written consent of Scholarly. 3