39 x 5 = (30 x 5) + (9 x 5) = 150 + 45 = 195
He did not change the sign of operation when 28 crossed the equals sign.
½ × 2 = 1
½ × 3 = 3/2
½ × 4 = 2
½ × 5 = 5/2
15/7 is approximately 2.143
Answer:
278.25 cm2
Step-by-step explanation:
If the width of the rectangle is x (cm), as the length is 8cm longer, so that the length of the rectangle is: x + 8 (cm).
In the attached image, we can see the length of each side. Total length of the sides are 90 cm.
=> (x + x + 8) + x + 8 + (x+8) + (x + x + 8) + x + 8 + (x +8) = 90
=> 8x + 48 = 90
=> 8x = 90 - 48 = 42
=> x =42/8 = 5.25 (cm)
=> The width of the rectangle is 5.25cm
=> The length of the rectangle is: 5.25 + 8 = 13.25 cm
=> The area of one rectangle is: Length x Width = 5.25 x 13.25 = 69.5625 cm2
As the 8-sided shape is made from 4 rectangles, so that:
Area of 8 sided shape = 4 x Area of the rectangle = 4 x 69.5625 = 278.25 cm2
Answer:
B
Step-by-step explanation:
First, we are decreasing the number so it has to be a decrease.
Next, we divide 7/31 and get around 0.23, which also represents 23 percent.
This only shows that 7 is 23 percent of 31, so we need to find the decrease by seeing the difference of 100 and 23.
We get 100 - 23 = 77, and because it is a decrease we get B.
