Donald is 38 years younger than Natalie. 5 years ago, Natalie's age was 3 times Donald's age. How old is Donald now?

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  24

Step-by-step explanation:

Let d represent Donald's age now. Then Natali's age now is d+38. The age relationship 5 years ago was ...

  (d+38) -5 = 3(d -5)

  d +33 = 3d -15 . . . . . eliminate parentheses

  48 = 2d . . . . . . . . . . . add 15-d

  24 = d . . . . . . . . . . . . . divide by 2

Donald is 24 years old now.

Alternate solution

You can also work this by considering that 5 years ago, Natalie's age was more than Donald's age by twice Donald's age then. Hence Donald was 38/2 = 19 at that time. Now, Donald is 19+5 = 24.

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.