If angle <a and <b are complementary but <a is four times as large as <b, find the measurement of a.

a+b = 90

a = 4 b

5 b = 90

b = 18
a = 4*18 = 72

To find the measurement of angle a, we need to use the information given.

Let's assume the measurement of angle b is x degrees.

Since angle a is four times as large as angle b, we can express angle a as 4x degrees.

Since angle a and angle b are complementary, the sum of their measures is 90 degrees.

So we can write the equation:

4x + x = 90

Combining like terms, we get:

5x = 90

To isolate x, we divide both sides of the equation by 5:

x = 90/5 = 18

Therefore, angle b measures 18 degrees.

To find the measurement of angle a, we substitute this value back into the equation:

a = 4x = 4 * 18 = 72

Therefore, angle a measures 72 degrees.