## marcoduuuh Group Title PLSPLSPLSPLS HELP. In the diagram below, is an altitude of ABD. What is the length of ? If necessary, round your answer to two decimal places. (Picture below.) one year ago one year ago

1. marcoduuuh Group Title

2. ZeHanz Group Title

First try to prove triangle ACB and ABD are similar. Similar triangles have proportional sides (meaning sides in the big triangle are a constant factor times the sides in the small one). Further hint: you may need the Pythagorean Theorem as well...

3. marcoduuuh Group Title

a^2+b^2=c^2. Where do I input 16 and 30?

4. marcoduuuh Group Title

16 = a, 30 = c?

5. ZeHanz Group Title

a and b are the rectagular sides, c is the hypothenuse

6. marcoduuuh Group Title

16^2+b^2=30^2 B= 25.38?

7. ZeHanz Group Title

No, a and b are the rectangular sides. In triangle ACB these are 16 and 30, so c²=16²+30²=256+900=1156, so c=34.

8. ZeHanz Group Title

So AB=34.

9. marcoduuuh Group Title

Now what do I do to find CD?

10. marcoduuuh Group Title

@ZeHanz

11. ZeHanz Group Title

ACB and ABD are similar, because they both have a right angle, and they have angle A in common. Similar triangles have proportional sides, which means:$\frac{ AC }{ AB }=\frac{ AB }{ AD }$ (read as: one side in first triangle : same side in other one= same number. Because in the above equation, you know 3 out of four lengths, you can calculate the fourth (AD). Once AD is known, you get CD = AD-16.