Please help me with this, image attached.

Mathematics

1 answer:

Ainat [17]3 years ago

5 0

Answer: x = 9 (choice D)

Assuming this is a geometric kite, then this means that triangle ABD is a reflection over the line BD to get triangle BCD. Furthermore, this points to AB and BC being the same length

AB = BC

3x - 5 = 22 .... substitution

3x - 5+5 = 22+5 .... add 5 to both sides

3x = 27

3x/3 = 27/3 ..... divide both sides by 3

x = 9

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eric has a riddle: " i am thinking of a fraction that is equivalent to 2/5 and the numerator is 18 less than the denominator." w

dezoksy [38]

Answer:

12/30

Step-by-step explanation:

So we know that the denominator-numerator=18

And we also know that it's equal to 4/10 or 2/5.

Soooooooooooooo the most easiest is just to trial and error: 12/30

But I don't really know the more complex formula...

5 0

2 years ago

Find the surface area of the composite figure.

ELEN [110]

Answer:

$644cm^2$

Step-by-step explanation:

First we'll work out the surface area of the pink figure.

That's the area of the two 5 by 6 rectangles on the top and bottom, plus the area of the two 5 by 20 and two 6 by 20 rectangles on the sides.

However, we note that the purple figure is blocking out a 6 by 12 section on the pink figure, so we'll need to subtract this.

The above works out to $2\times(30+100+120)-72=428 cm^2$ .

Then we'll work out the surface area of the purple figure.

This will be the area of the two 4 by 6 rectangles at the top and bottom, plus the area of the two 4 by 12 and one 6 by 12 rectangles on the sides. Note that there's only one 6 by 12 rectangle because the other face is joined to the pink figure, so it's blocked out.

That's $2\times(24+48)+72=216cm^2$ .