Geometry: Problems involving similar triangles??? Pls. answer it, i'm begging you pls. pls.?

Question

1. At a time of the day when the shadow of a vertical pole 20 ft. high is 28 ft. long, tree nearby casts a shadow 35 ft. long. How tall is the tree?

2. The ratio of similitude (or scale factor) between two similar triangles is 3:4. If the shortest side of the smaller triangle is 21 cm, what is the lenght of the shortest side of the bigger triangle?

3. The lenghts of the sides of a triangle 8, 10, and 12. The lenght of the shorter side of a similar triangle is 12. Find the lenghts of the other two sides.

4. The lenghts of the sides of a triangle are 14, 8, and 16. Find the perimeter of a second triangle similar to it, if the lenght of the shortest side is 12.

5. The perimeter of two similar triangles are 14 and 24. The lenght of an altitude of the first is 3. Find the lenght of the corresponding altitude of the second triangle.

6. Shad is 3 ft. from a lamppost that is 12 ft. high. If Shad is 5 1/2 ft. tall, How long is Shad's shadow?

Answer 1

Oh, simple!! Come ON, now. Tell ya what, I'll boil each of these down to the calculation you need to make to solve it. I'm sure you know how to equal two fractions.

1. The pole's shadow is 28' long, and the tree's shadow is 35' long.. 20/28 = x/35 I think you can figure that one out!

2. 3/4 =21/x

3. 8/12 = x/10 and 8/10 = y/12

4. 8/12 = x/14, 8/12 = y/16. 8+x+y=perimeter of 2nd triangle.

5. I'm not sure about this one. You don't specify whether these are right triangles or not, and I'm not spending all MY time figuring out YOUR homework!! How will you learn?

6. Employ what you may or may not have learned, and find the conclusion yourself. It might help to draw some diagrams.

Answer 2

(1) 20 / 28 = T / 35; solve for the height of the tree T

(2) 3 / 4 = 3.4 / S; solve for the side S

(3) 8 / 12 = 10 / S2 = 12 / S3; solve for the sides S2 and S3

(4) similar to (3); find the three sides, then add them up.

(5) 14 / 24 = 3 / A; solve for the altitude A

(6) 12 / 3 = 5.5 / S; solve for the length of the shadow S

Answer 3

1.The tree is 25 feet tall.

20 _____ X
____ = _____

28 _____ 35

Multiply 20 by 35 and then divide by 28.


2. 28cm.

3 ----------- 21
_____ = ______

4 ------------ X

4 times 21 = 84
84 divided by 3 = 28.

3. 15, 18

8--------- 10 -------- 12
____ = _____ = _____

12 ---------X ---------- y

12 times 10 = 120.
120 divided by 8 is 15.

12 times 12 is 144.
144 divided by 12 is 18.

4. Perimeter = 57.

8 --------14 ---------16
____ = _____ = ______

12 --------X --------- Y

12 times 14 = 168
168 divided by 8 is 21.
X=21

12 times 16 is 192.
192 divided by 8 is 24.
Y = 24.

But since you need to find the perimeter, you must add up all of the sides.
12 + 21 + 24= 57.

5. I wanna say that it's 5.

6. umm.. How long is the shadow of the lamppost?

Answer 4

too many questions at one time, try reasking the ones I don't answer
1} 20/x=28/35
28x=700
x=25

2} 3/4=21/x
3x=84
x=28

3} 12/8=y/10
8y=120
y=15
12/8=x/12
8x=144
x=18

Answer 5

If you draw these, the answers will be obvious to you.
Similar triangles are same shape triangles; or same shaped triangles upside down.