SOLUTION: A rectangle has a width of 4 cm and a length of 10 cm. The rectangle is folded so that it creates a rectangle with a width of 4 cm and a length of 5 cm. The other rectangle has a w

Algebra ->  Distributive-associative-commutative-properties -> SOLUTION: A rectangle has a width of 4 cm and a length of 10 cm. The rectangle is folded so that it creates a rectangle with a width of 4 cm and a length of 5 cm. The other rectangle has a w      Log On


   

Question 1196938: A rectangle has a width of 4 cm and a length of 10 cm. The rectangle is folded so that it creates a rectangle with a width of 4 cm and a length of 5 cm. The other rectangle has a width of 4 cm and a length of 5 cm. Write two expressions to show the area of the rectangle.
I got (4 x 5) + (4 x 5) and (4 x 5) x 2.
I am not sure if the expressions I got are correct, but I think they are because the rectangle has to have an area of 40 cm. Can you please help me with this question?
Found 2 solutions by josgarithmetic, math_tutor2020:
Answer by josgarithmetic(39615) About Me  (Show Source):
You can put this solution on YOUR website!
Think:
The pair of addends which give sum of 10

Come back to the problem and what you need will be obvious.
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BEFORE THE CUT
Area, 4%2A10


AFTER THE CUT
Area, 4%2A5%2B4%2A5 or 2%284%2A5%29

Answer by math_tutor2020(3816) About Me  (Show Source):
You can put this solution on YOUR website!

The 4 by 10 rectangle has a line down the middle to make two identical 4 by 5 rectangles.

The original 4 by 10 rectangle has area of 4*10 = 40 square cm

The smaller rectangles have area of 4*5 = 20 square cm each, so that doubles to 2*20 = 40 square cm.

We can either say:
4*10 = 40
or
2*(4*5) = 2*20 = 40
or
4*5 + 4*5 = 20+20 = 40

What you posted of 4x5+4x5 and (4x5)x2 are both correct. This is of course assuming the x refers to multiplication (and not a variable). I used the asterisk symbol * to represent multiplication in the work shown above.